The Magic Treehouse series is fun and touches on many historical events.

A great biography series is the "Who Was?" Series. It covers many people and many time periods.

I also like the "If you Lived" series.

What I look for in history genre books for younger children is accuracy. Obviously, young children are often unable to process complete accuracy about events such as Thanksgiving, but feeding them a completely fictional story in order to deal with the age issue is not necessarily the best idea. This is why I recommend these three series.

When I was a kid I was hooked on all of the Horrible History books, they made me laugh and really got me interested in various parts of history.

Once I started being really hooked on Roman History I started to read Caroline Lawrence's 'The Roman Mysteries', a fictional series that sort of fleshed out that time period in a fun way.

So those would be my two shouts!

As an avid reader of books myself in most cases, I have to second the recommendations of Pghtoad's Magic Treehouse series. The Magic Treehouse series is simple enough for young children to understand, with at most some help from an adult to explain some terms they may not know. However, do take caution in picking out the books, since some of them are set in more fantasy-esque settings, even though the premise of the series itself isn't completely realistic either. You can also refer to the companion books for the children to learn more about the respective eras or people.

Depending on the specific era of history they show more interest in, adapt the choices of books. For example, if some happened to be more interested in the Second World War and showed enough reading proficiency, you could possibly give them The Boy in Striped Pajamas, since that portrays the reality of what it was like to live during the era without being too confrontational about it. It's likely that the children reading will be approximately the same age range as Bruno, so this book could possibly teach them to empathise with the Jews' perspective during the war. Keep in mind, however, that this book has been criticised for historical inaccuracy (which I will admit can be pretty glaring, and a lot of explaining will likely need to be done to correct the errors among other things). The Book Thief by Markus Zusak is long one of my favourite books, but it can be pretty gruesome for younger innocent children. Keep this for the older bracket in the target group, and even then note it is likely to be historically inaccurate here and there as most stories are.

I recommend some more encyclopedia style books like The History Of The World or other similar books, since they present factual evidence in a more formal and organised method, and can help the children identify specific areas of history they may have interest in. This method worked on most people around me, seeing as we all have cultivated a love for history. Keep in mind, my pastime was basically reading an outdated adult's encyclopedia of information in elementary school, so I may not be the best source for this. However, as long as the encyclopedia's terms were simple enough, I think it's fine to use any encyclopedia to cultivate a love and attention for the finer accurate details in younger groups, as well as provide backdrop for the stories they may read outside of these books.

(I was also soft to any book in the Horrible series like LITCsam, no matter which section it is - Science, History, Geography - as long as it was informative enough. Give a young child any of those and I think they'll be set for the day. As a child, I probably spent way more of my time reading about various different eras, especially the Greco-Roman era, although my love for history is caused more by the variety of styles resulting from the large range of stories behind each event. It's safe to say that some children will be bound to discover a passion for the topic at some point in their life.)

We're five posts into the thread and no one has said American Girl books yet? :(

I'm not saying they're exquisitely accurate or unproblematic from a feminist standpoint, but they're fun, light, and engaging. Felicity is the best (I will fight you...but I won't have to, because you know I'm right), followed closely by Addy.

By way of picture books, I really like the "You Wouldn't Want To..." series. The medieval ones (build a medieval cathedral, be Joan of Arc) are actually quite responsible! I have been really impressed with the nuances of medieval life that they are able to convey.

And then the best book of all isn't historical fiction--it's about other kids who are interested in history, a different sort of inspiration. And that would be Zilpha Keatley Snyder's The Egypt Game. It's about a PBS special-diverse group of friends (based on some of the author's own students, extrapolated backwards to childhood by her imagination) who take over an abandoned lot behind an antiquities/thrift store and LARP ancient Egypt. Complete with royal rituals and an altar to Set.

It's awesome.

Nothing caught my kid's interest like a civil war battlefield guide and a trip to Gettysburg. Watching him read sections of the book and then looking out and seeing where it happened was truly wonderful.

Mine are middle school aged, but I've started reading them The Fall of the Roman Republic, which is a collection of Plutach's "Lives" following Marius, Sulla, Pompey and Julius Ceasar. They're whole engrossed in it.

The best part is that both the subject and the author are from antiquity

There are some really great suggestions on this list, I just wanted to put in a plug for /r/History's Young Historians List which we just added.

The Horrible Histories books I feel are great for getting kids into history. I think it's the tagline of "history with the nasty bits left in" and the idea that "schools don't teach the interesting stuff" makes them feel quite taboo for young kids and therefore more appealing. And of course, there's also a corresponding TV show made by the BBC that's brilliant, for adults as well as kids.

I also loved the 'My Story' series of books growing up. Written by lots of different writers, but they're 'diaries' of people in different periods of history. They literally cover from the ancient Egyptians (one book follows a girl named 'Asha', and the plot twist at the end is that she grows up to be pharoah - the way it's written makes it seem as though her sister is in line for the throne), right up to WW2, covering all sorts of countries, social standings etc.

These are really great because, despite being fiction, at the end of the books they have a timeline of the era they're based in, and also a 5-10 page summary of the history of the era. I'm 19 now and in my second year of a history degree and I still read these every now and again, I cannot recommend these enough.