The book was in like you said 1979 since then holdem and poker has advanced so much, and the game has gotten harder.. espceially after the poker boom, where thousands of players now play.. share strategys, and information even developing poker training websites for other people to learn.. also since people have been playing holdem for so long, the game has become dried out & many people understand all the basic concepts of how to play.. the book is a classic because it was the first real book that showed all the advanced guides on beating the game, but in todays age it is completely dated.. their are some very good sections in there however like the 7 card stud section by chip reese i believe, which can be still applied.
Doyle has had to adjust his game just like everybody else, if you want another book or training i would suggest trying to watch some learn from training videos, or reading a book like beating the micros by blackrain79 he offers some great tips.. that is for cash games however, tournaments are a different story.

I guess is more of a collectors book then a bible..

It was good for its time. But its a little out dated now as alot of players have counter fitted this style. But it still one of the best around

I know guys who have alot of success using this as a bible!! I guess its horses for courses, find a source of info that suits you, that you trust in. Doesn't mean you will win though!!!! You still need a bit of nous and loads of luck!! I have read most of it myself now but struggle with the timbre.

Online poker changed a lot...think its good to play today against pokerschools and pokerbooks tipps..its helpfull.