There are tips and tricks to figuring this out, but they are just general rules and always have exceptions.
First rule is bibliography. A long essay, just the author reflecting on abstract/meta issues, isn't expected to have a lot of sourcing and bibliography. A book that offers, for example, The Empire of Cotton (Sven Beckert's 2014 opus), on the other hand, is expected to cite sources. If a history of Benjamin Franklin cites little to no sources it is a bad sign. If a book is describing the history of television and cites little to no sources, same thing. Even books geared towards general audiences should, if they're serious, cite the works they're based off of and cite them often.
Second rule is, what bibliography is used? If someone is offering a pop-history account of the life of Andrew Jackson it is completely normal for their bibliography to be mostly made up of other authors who have written on related topics. The problem with this is that those authors selected specific sources to make their points. The guy you're reading didn't actually read the original letters. He read the fragments of the originals as cited by others. The other people who wrote had their own agendas and perspectives and cited sources that support those arguments. You're getting a summary of a summary. And the person you're reading may not even be accurately representing the views of the author they are citing (recently this appears to have happened with a podcast where the podcaster mentioned a 'clause' as if it were a treaty when it was a verbal 'policy' of a given government and never codified into national or international law). A serious author should demonstrate that they have consulted primary sources at some point in their work.
Third, who are they? Not all great histories are written by university professors. Indeed, non-academics write great stuff all the time. Buuuut.... If you're going in blind it is a good idea to see if this person has any training in history. If the author you're checking out got a degree in creative writing, a great book of history is possible but as unlikely as a Linguistics major suddenly putting out a great work on economic theory.
Fourth, who is recommending them? Usually a book has blurbs (ie. 'A masterpiece' says so-and-so). Do you notice that none of the people recommending the book are actual historians? Like, maybe a news network (CNN, Fox, MSNBC, etc.) host recommends it and some obscure newspaper that sounds legit but you have never heard of, but no historians. Or, maybe one historian, but from a really obscure university and who (if you look them up) doesn't have much published themselves. A lot of history is reputation. If no serious author in your field is willing to go to bat for you, it is a bad sign. Again, not impossible that it is a great book and will in time become a classic. Just not likely if you can't get anyone to give you as much as a blurb.
Fifth, who cites this book? Try looking up the author to see if other serious books in the same field mention the author and see what they say. Google Books which often include scans which you can read free online. Maybe the author you're looking at is universally derided. Maybe it is even worse; irrelevance. If no one thinks to cite that book and it has been out for a while, it is a really bad sign. Another way to check this is to hop onto JSTOR and other online resources to see if the book has been reviewed there. Good books may slip through the cracks and not get reviewed, but if they pop up on JSTOR it is at least a good sign that it was relevant enough to spend the time and space necessary reviewing it at all (though you might also want to see what the reviewer had to say).
These are just some basic tips.
Hope it helps.
Your best bet would be first to make sure that the book comes from an academic publisher (Oxford, Cambridge, Yale, or any other university press, along with other non-university academic publishers like Palgrave MacMillman and Routledge). Looking only for academic presses can be limiting, though. There are many, many good history books that are published by non-academic presses. Farrar, Strauss, and Giroux normally publishes very good history books, as does Penguin, W.W. Norton, and many others. Besides that, look at the author information in the back flap or the very beginning of the book. Does this person have a PhD in history or some other advanced degree related to the topic of the book? Or does the author have some practical experience (government job, non-profit work, etc.) with the topic being written? If so, there's a good chance the book will be fairly reliable.
Of course, these are just general rules of thumb, not ideal markers of what makes a book reputable or not. There are many good history books by people with very little professional training in history, and there are also bad books that are published by academic presses. Really the only way to ensure you are reading a credible history book is to be very fluent in the topic you are reading about and knowing who the major authors are. This can only come with a lot of time and experience, something the average reader doesn''t want or need. With that being the case, the above suggestions should by and large protect you from most of the bad history books.
I'll expand on how to quickly gauge a book's quality with some examples from books that I've pulled from my own shelves.
This one is pretty straightforward. It's from an academic publisher, and I can see from the author description that he is a professor of history at the London School of Economics and Political Science. Furthermore, the book won the Bancroft Prize, an award decided upon by academic historians from Columbia University. This can easily be considered a reputable book.
This one might be a little bit harder to gauge, but still, it'll be pretty easy to determine that this is a reputable book. The publisher is not an academic press, but I can see from the author bio that he is a professor of history at the University of Virginia who has published extensively on U.S. Cold War foreign policy. Another good, if sometimes superficial, way to gauge a book's credibility is through the blurbs written on the back. All of the blurbs praising this book are from noted historians from top-tier universities. We can easily see that this book is reputable.
This book's a little bit different. It's published by an academic press, but as the author bio says, the author is a professor of journalism and telecommunications, and has a PhD in political science and a J.D. from Seattle University School of Law. This author, as we can tell, doesn't have a professional background in history. His background in law, though, seems to show that he likely knows what he's talking about in regards to the Bill of Rights. That it is published by an academic press gives it greater reputability. Again, this book will likely follow at least the basic tenets of what makes a good history book.
This one is also more difficult to gauge, but should still be pretty easy to see that it's reputable as a historical work. The authors are not historians, but have worked as journalists and non-profit workers within Afghanistan for the previous 40 years. It's published by an academic press, and, within the acknowledgements section, we can see that the authors sent drafts to noted academics in the field they are writing about. Again, this book is easily going to be reputable.
This one will honestly be difficult to determine if you're unfamiliar with the field, and you will need to dig a little deeper to see if this book is reputable. The author is a journalist, not a professional historian, and the book is not published by an academic press. The blurbs from the back are all from other journalists or government officials. If you're unfamiliar with the author, this is when to look for book reviews for both the book you're looking at and any previous books the author has written. If I were to search for reviews of previous books, I would see that this author has written a couple of history books that are highly praised by professional historians. This book is most likely going to be reputable.
This book is neither written by a professional historian nor published by an academic press. The blurbs for the book are written by prominent authors of fiction (particularly spy thrillers), and the only thing that the other blurbs from Newsweek and The Christian Science Monitor say is that the book reads like a fiction spy thriller. Certainly not a very ringing endorsement for anything relating to the the author's abilities as a historian. Obviously, a book that should probably be avoided.
I've tried to give you examples that can account for most of the different types of history books and authors. These are the exact things that I question any time I'm looking for a new book or am thinking of buying a particular book. While these books are mainly from my area of expertise, I hope this gave you a general idea of what questions to ask when looking for new history books.
Yes.
Maybe not 'easy' per se, but as you read more and more about a particular subject, you begin to run into repeated names in the subject, especially when you check the cited sources. So, if you're studying the Salem Witchcraft Trials, you're likely to come across Boyer and Nissenbaum, Carol Karlsen, or Mary Beth Norton rather routinely, as they were large names in the field of pioneering research. The Witches by Stacey Schiff, which I received for my birthday recently, is a great example: one look at the sources for the book and I note all of their names. Since these three were pioneers in the field, this makes me feel comfortable with The Witches; if instead, I had found a bunch of books attributing the witchcraft craze to ergot poisoning causing LSD like reactions, with no recognizable names, I might have felt different and less trusting.
In presidential biographies, Arthur M. Schlesinger Jr. or David McCullough or H.W. Brands might play a bigger role as you read more. While you might pick up a McCullough biography, he tends to write doorstoppers and so, like Schlesinger, he is just as likely to appear as a source in a book. Seeing either name, in the cover or the sources, will make me more comfortable. To take an example from Half Price Books yesterday, I am liable to believe reputed historian Arthur Schlesinger, especially on the subject of Roosevelt; I was actually looking for his first volume on Roosevelt. Instead, I found a book called The Roosevelt Myth with a picture of Roosevelt and Stalin cackling together on the phone while Roosevelt quips, "I'm glad you found your constitution, Joe, I can't find mine!"
One of these, as you might expect, is more liable to send up red flags. Is the historian in question making outrageous claims? If you get the feeling that an outrageous claim is the essence of the book, it's probably not reputable. On the same note, a book that claims to have sources without providing them also tends to send up red flags. From what I've heard of it, the Killing series by Bill O'Reilly is a particularly egregious offender here.
Continuing the subject of sources, what are they? Does a book rely purely on secondary sources (what other people have written about the event), or does it, like the Witchcraft historians above, consult the surviving testimony and records from Salem? McCullough would have a hard time writing an authoritative Truman biography if he only read previous Truman biographies, secondary sources, rather than also consulting Truman's personal writings, including his unpublished papers and other extent primary source material about him.
As you begin to find a level of familiarity with works, you begin to understand the biases of different authors, the way they approach issues, and you can compare and contrast the different way that they discuss the causes and ramifications of events. By understanding the approach of historians and their school of thought, you can decide whether you're more liable to turn to Peter Ackroyd's arguably more 'liberal' Foundation and continue his series or to Andrew Roberts more 'nationalistic' or 'conservative' A History of the English Speaking Peoples.
The school of thought that informs a historian's approach is particularly relevant: is this a social historian, who views history as occurring from the bottom up? Or one who views history in the 'Great Men' tradition, as my college professors called it, and see development in a top-down system? Or does the historian subscribe to neither, believing history to be a little more complex than such a strict dichotomy?
So, for example, to harp on a recent example I've used, Amity Shlaes' biography of Calvin Coolidge immediately set off red flags by presenting a version of history I found so at odds with what I've read in other books and in college that I was astounded. Even before picking it up, however, a little research and skimming showed me that there would be a high level of bias.
Reputable biographers and historians tend to help out and make a very clear impression when you do read them. McCullough or Brands, if memory serve, will often present a panoply of different opinions on a subject's action. In Truman, for an invented example, McCullough at some parts discusses that X biographer describes Truman's behavior in such and such way, Y biographer does it in this way, Z biographer does it in such way, etc. Most books that do this tend to be heavy and weighty, admittedly, and aren't much fun to read: The Yellow Cross by Rene Weis, which I just finished trudging through recently, I would put in this category as well. The above referenced historians about the Salem Witchcraft Trials are excellent about this too-although it did make the reading for that class a headache.
Other historians will offer such snippets or anecdotes of history to flesh out what is being told, and tend to root the book more firmly by giving accurate precedent. Hopefully that helps!
Thanks for asking a great question! I learned a lot from the responses.