I'm a very new player and after reading this book I'm even more confused. The sections about postflop play and adjusting to stack sizes really do not line up at all with how people play today. It seemed incredibly tight. Is this book from another time in poker or is it just me and this really is a good way to play?

Nope, still a good book. The section on swapping mistakes was gold. Have a nice day.

I would say yes, very outdated, I am not surprised at all that you are completely confused.

Truth is, already when the book was released it was kind of a strange "avant-garde" book... Despite the title it was way too theoretical and not achieved, and I would never have recommended it to a beginner unless you want him to be completely confused about the game...
Also a lot of practical topics that are crucial for the beginner, are either omited or treated too vaguely (like the importance of agressivity, how to c-bet, board texture, ranges, etc...)
I think that a more truthful and suitable title would have been: " Research & ideas on NLHE ".

It's not that the book is bad, there are a lot of interesting things in it, but it's certainly not written in a way that you can put those things easily in practice for a beginner.
A lot of better, clearer, more organised and more beginner friendly material is now available.
For me it is exactly what you said: "a book from another time".

I agree with all that. In a contest between it and newer books, or it and say, the applications for no limit hold'em discussion thread, it's old hat. But for a very new player who is debating whether to try gleaming an idea (or a few) reading NLHTP, vs. reading nothing, I figured reading the old concept book would be superior.

If Op is looking for confirmation that it's old, there's no debate here, if he's looking for confirmation that it's bad, I'm not 100% confident that it's not worth a read for someone trying to be a serious player and attempting to ensure they've at least read and considered the literature out there. No harm reading and disregarding some of it, or hypothetically disregarding even most of it (I assume disregarding all of it's points would lead to some sticky/****ty spots and overall poor play.)

Maybe this a good jumping off point for a discussion on some of the old axioms, and how much value and relevance they havr lost, or retained, in today's games. For instance, "playing tight in the back and loose in front" is damn near prehistoric advice, but it very likely still holds water. I'm reminded of chess and how certain openings would go out of style for decades only to eventually see new crop of experts bring back the old school with a vengeance, and probably for good reasons, just like they went out of style for what were considered good reasons.

In keeping the chess comparison I'm going to assume Op is a club level poker player looking to improve, he may be a little worse, or a little better, but it's very unlikely he's "special" at poker, so one of the first things he'll want to get comfortable doing is analyzing the pros and cons of any specific decision, and his reasoning behind said decisions. "It depends" is often a vague but honest and accurate answer, obviously.