I'll just flag
@Ruin Explorer . I believe he is a historian, so may have something to say on this topic.
Only by degree sadly, I used to a legal researcher and am now in legal tech.
That said some of the principles in research hold.
So, historians of ENWorld, if I want to read an approachable history book without being a historian myself, how do I know if I'm reading something up to date, or if I'm just filling my head with nonsense?
First off, the guy who was being rude to you sucks.
I mean, sure you sometimes get people acting like they're experts because they read one dodgy book or worse watched one Youtube video, or even worse, read one tweet, and it can be hard to resist not taking them down a peg, but I very much doubt that was what you were doing, based on your posts here.
But like,
@Umbran puts it really well here:
Well, first and foremost - a book cannot be up to date if it isn't recent. Check the copyright date.
From there, do a bit of googling about the author - if they are widely considered a chucklehead, avoid them. Reddit's "As a Historian" can be helpful. Reviews on Goodreads might also give you some insight.
I'd add to things to this:
1) Re: Goodreads, a lot of people voting on there trend pretty hard towards not liking anything that's too intellectually challenging and/or doesn't fit their biases (whether fiction or non-fiction), but that's often evident in their reviews so fairly easy to account for.
2) Re: up to date - some areas of history and archaeology move a lot faster than others. There are books from early last century which still have some relevance (usually only seriously academic ones though, which won't be what you'll be buying), and there are books published 5-10 years ago which are already out of date. And everything in-between. So this can be tricky - but if you're looking at a specific area of history, you can probably find out fairly easily if there's been a lot of change lately.
Oh yeah and re: chuckleheads, one thing you can always do is put author name and controversy into Google and see what comes up. That there is controversy doesn't necessarily mean the author is bad or wrong, but you might want to know what people are saying.
Points others have made re: bibliographies are also very good, if a bit harder to engage with when new to the field.
For real? Thanks for the pile of straw men. Just because ancient aliens don’t exist doesn’t mean there isn’t a whole lot of uncertainty about Alexander, Viking raids or even NYC in the 70’s. I presumed the OP was a genuinely curious person studying real history, you should maybe apologize to him for assuming he shared your obsession about weird stupid stuff.
I mean, you're proving his point here. None of what he listed are "straw men" nor "weird stupid stuff", and whilst they're more extreme examples, there are things that certain books, particularly older ones, get terribly wrong (often contradicted by more recent archaeology).
One of your examples is particularly questionable - Viking raids - there is actually a huge amount of uncertainty about them, particularly re: who in Scandinavian societies were doing them, how frequent they were, who they targeted, what equipment they used and so on. A history book from 1950 or to a lesser extent 1980 is going to have a lot of stuff that is indeed outdated and wrong.
Even the study of Alexander's conquests has changed a fair bit over my lifetime, despite people being obsessed with them for centuries. Though certainly less so than some fields.
I will note that unfortunately recency can't entirely eliminate nonsense, because there are still cranks like Graham Hancock out there - who published a book last year which is absolute nonsense of the highest order.