The Bill James Historical Baseball Abstract is a massive tome of baseball opinion, trivia, and statistical analysis covering Major League Baseball from the 1870's to today. It is available in four flavors. The first model was the original hardcover, first released in 1985. The paperback version, released in 1988, featured updated information on the 1980's. That was how it stood until 2001, when James released the much-delayed New Bill James Historical Baseball Abstract. While it repeated in places, it was almost entirely a new book. A paperback version was released in 2003, and featured an article in the back which updated player rankings based on their 2001 performances.
Section one of both books is "The Game." It is pure Bill James, with just about anything he finds interesting thrown in and articles going off on tangents as he sees fit. His wife, Susan McCarthy, provides summaries on baseball uniforms through the years and even provides rankings of the best and worst looking major leaguers of each decade, a task she handed down to their daughters for the sequel. Both books, while they feature different content, are similar in this section.
Section two is "The Players." In both it provides his rankings of the best players of all time and at each position. The difference is in how he ranks them. In the first one he used traditional sabermetric methods, such as his own Runs Created and Range Factor, as well as analyzing contemporary accounts of the players. In between the two books, however, James developed Win Shares, which he combined with the subjective accounts of the first book. The rankings are, as a whole, far more cohesive than in the original.
The final section is "Reference", which in the original was simply a mass of statistics on the players he talked about in "The Players" section of the book. In the New version it's a sample of selected Win Shares statistics for the best players of all time, as well as some of the best and worst teams of all time.
Both versions have garnered rave reviews over the years and are considered some of the best baseball books ever written. The paperback version of the New Abstract is still available in stores; other versions will need to be purchased elsewhere.