I don't think historiography is as binary as you're making it out to be.

Each successive generation has its own biases, and this requires history to be constantly rewritten. Just because we've identified the biases in an older piece of work, it doesn't mean that work is useless, it just impacts how we use it. An "obsolete" history might still prove quite useful.

The only answer to this question is to read quite a few books on the same topic. This is, essentially, what general fields are for in American doctoral programs - to inculcate this variability and a critical approach to the text itself. Books that deal with race and the Civil War from the 1950s will almost certainly be more obsolete than others due to social biases, etc, but there's no magic point at which an entire generation becomes useless.

Oh man, thank you for asking this question. Pretty much this exact thing (granted, with a heavy focus on the ideological/political factor) used to bother me to such an extent that I ended up shifting from an original interest in history into historiography itself. I did my BA and MA then got into a PhD program in three separate academic areas which appear at first glance to be freakishly divergent but are tied together by, among other things, the concern you've raised in this post. Bonus is I did it here in the PRC and have Hucker right over there on the shelf- even if I haven't exactly looked at that one for a while.

Everything telkanuru said makes sense, also it's not my area but I'm sure all the authors of the newer, snazzier Civil War histories have probably read Foote. For China Studies abroad, all the Ungers and Jensens have been through Watson and Waley and Fairbank- hell, Pamela Crossley studied under Jonathan Spence. Historiography is the history of history and diving into texts which now may be discredited but nevertheless in their time had the power to shape their fields as well as the popular understanding of an entire era is valuable for that reason alone. Once I got over my refusal to waste my time with the Orientalists or the pro-US establishment foreign policy wonks of the Cold War or the pro-Sinification camp or whoever, it turned out that you can start looking at these kinds of works as something approaching 'primary sources' in themselves. The book that did it for me was a certain English language history of Korea that I picked up when I really needed to get away from PRC ordained, 100% ideologically-driven texts. This book ended up being older than I thought and just as guided by agenda. It was written in the late sixties and had little interest in objective history, reading better as a polemic on Korean nationalism and an as-yet hardly stable South's imagining of itself in relation to the North. Regardless of purported content, you learn less from a book like that about Koguryeo and Unified Silla and more about how ideology worked under Park Chung-hee. You go into this kind of text aware that things will be "off," and that influences how critical your reading will be. Hopefully, that suspicion carries over when you're reading the new, hot thing of the moment, because in a few years' time, today's scholarship will also be surpassed. Historical study will always be subjective, new views and powers will appear and become fashionable and dominant in their turn. Every author writes under the influence of some position, having been exposed to a finite amount of sources and texts and other scholars, and, by definition, at a far remove from their object of study. No one is able to present history "as it was." So once we understand the questions presented by older texts by simple virtue of their age and the changes occurring since their publication, it's probably best to be asking these kinds of questions of everything we read.

Historiography for non-historians. This is a good topic. One of the challenges in being a historian is understanding the context of what you're reading. This allows you to make good judgments and really understand not just what you're reading, but what the writer is trying to accomplish.

Best thing for a non-historian to do is, if a book seems revelatory to you, do a search for book reviews from a variety of sources, or look for a Wikipedia article on the historiography of your subject.

It doesn't really matter "when" a book was published. What matters is the author and the material they had access to, all of which is hard to evaluate without training or prior knowledge. There are plenty of books that are still accurate and considered essential reading from the 1950s and even before.

When I was young, I was swayed by several books I read that just seemed great, but then once I got to college I learned that they were pretty much bunk. It's sort of like how non-historians believe in Gavin Menzies' "China discovered America" stuff. It sounds okay to someone without prior knowledge or training, but anyone who has that recognizes the flaws immediately and doesn't take his stuff seriously.

Usually a Google search of "(TOPIC) historiography" will bring up some sites that will give you some context.

Or, like telkanuru wrote, read several books. For example, if you want to read on the Civil War, look up lists of "essential reading." Often, the lists will come with descriptions that mention the books' contribution to historiography.

History is always changing, so you'll never find a "definitive" book (although the word is tossed around a lot and some books come close), so don't ever assume you know everything about a topic. Prepare to be proven wrong, and you'll do just fine with reading history.