This book is the absolute best Civ 2 book. Bar none. It is also the best Civ 2 reference book available. Do not even bother to buy other Civ 2 books; I have read them all and most are a waste of your money, esp. the worthless book by Jason Rich.
This book has excellent suggestions for beginners and intermediates, and is invaluable for experts as a reference. Many of the details of the game are simply not found anywhere in the game's original documentation, but are explained very well in this book. From this excellently formatted wealth of information, one can deduce many advanced strategies of the game.
There are a few minor errors which advanced players will eventually notice (eg, page 309 concerning subversion), but these are very subtle and probably won't be noticed by most beginners and intermediate players.
This book is easily worth the price. If you like Civ 2 (or wish to play and/or understand it better), this is the book for you. This is the first book you should buy after you get the Civ 2 game.