Scarne's encyclopedia of card games is a rather extensive guide to games played in the US and Italian games. The book contains a lot of variants for games played in the US (including a lot of canasta variants), plus a couple of games invented by the author.
Many European games are missing, for example German skat. (The book contains only the US Skat, which is a different game.) The book was written in the 70's, so there are no new games such as spades or hand & foot, or any games of the Asshole / Big Two / Great Dalmuti family.
The book is organized by family (such as "Pinochle family" or "Whist family") rather than type ("Point trick game", "meld-scoring rummy"). In my opinion, this organization makes the book easy to browse, except that ordinary rummy games and meld-scoring rummy games are not separated. (There are separate chapters for Canasta & variants and Gin & variants, though).
The prose is at places poor, and entries for individual games are ill-organized. It is difficult to use the book as a reference, since finding the rule you are looking for is difficult. However, there are only a few amiguities in the rules.
The book is somewhat money-play -oriented. For example, the chapter for banking games is extensive. There is also an extensive chapter for finding out who cheats. In the rules of all games, handling irregularities and rule violations is extensively explained, which is important for money play, but is of little use for casual or intellectual players.
+ A lot of variants for common games
+ Structure of the book
- Poor prose
- Emphasis on money play
- US centric