brunson's super system is the best book available to read and learn.
I concur, and that's where I'd suggest anyone interested in learning start with
Super System. Anything by Sklansky is good, though you'll have to work to understand the concepts as they are highly mathematical. Sklansky's "For Advanced Players" series is also excellent and well worth consideration.
I think this book is way outdated & for myself it wouldn't be on my Top20 poker books.
This is true only on a very superficial level. Games such as Five Card Draw and Draw Low are rarer than seal feathers in today;s cardrooms. Straight Seven Stud H/L was on its way out of favour when the book was published, and the first edition never discussed Stud-8, nor Omaha. That doesn't mean that there aren't any useful concepts to be found in those sections. They are definitely there.
As for the rest that remains relevant to today's Poker scene, The games haven't changed, and the advise and concepts are still as apropos now as the day they were written. Hold 'Em is still Hold 'Em, and played the same. The only things that have changed are that Hold 'Em is a helluvalot more popular these days than it was when
Super System first appeared (when the Golden Nugget was also known as "The House of Hold 'Em as they were the only cardroom that spread the game on a regular schedule) and many cardrooms had placards to explain the game to passing tourists. Back when the only NLHE games to be found in 'Vegas were
wsop side games, and now when it's the peoples' choice and pretty much available everywhere, and FLHE games are few and far between.
Fads and fashions change, but good information remains good information.