How useful is a 40-year-old chess book? I have a chess book which I find great in terms of tone, formatting, etc., but the computer does not agree with some variations I gave it.

How much has chess changed since 1977? I imagine the rise of the computers (and computer chess) the last couple of decades had quite some impact. Is my book (published in 1977) still worth reading?

I'd like to know before I buy the other books of the series.

Addendum
The series in question is "praktische schaaklessen" (practical chess lessons) by Euwe. The book I have is on opening theory, but the other parts are on the other aspects and stages of the game (it's a six book series).
This depends on a lot of things, but most importantly: your playing level and the topic.

For example, if it is an opening book, it heavily depends on the opening. Some opening variations which are main stream today, didn't even exist in the seventies, or were rarely used (like the Berlin Wall in Ruy Lopez). Others haven't seen that much development (QGD, and offbeat openings like the King's Gambit).

Middlegame &amp; strategy books usually last longer; Nimzowitsch' Mein System is 90 years old but still a useful read.
The same is true for endgame books, with one notable exception (which doesn't appear that often in practice): endgame tablebases have completely changed the view on certain endgames like K+Q vs. K+B+B (thought to be a draw, now known to be a win for the Q) and K+Q vs. K+N+N (the other way around).

If you are a &lt;2200 player (like me), you shouldn't worry too much about computer evaluations. Though it is a very good practice to analyse the lines given by the books, so kudos for that.