If you're interested in baseball, this is an essential book; it's tempting to stop the review right there and simply direct you to the "Add to Basket" button. For your money, you get a huge volume that effectively combines two books: in the first half, a decade-by-decade history of the sport, charting its evolution, then in the second half James applies his new statistical metric, "Win Shares" - an attempt to compute the contribution an individual player makes to his team's record and thus his overall value compared to others of different teams or different eras - to compiling lists of the 100 best players at each position. As previous readers of James's work will know - or, indeed, anyone who's simply aware of his guru-like status among some baseball fans will guess - James is reluctant simply to pass on received opinions and is always ready to sink his teeth into a woolly generalisation or piece of conventional wisdom and ask its upholders to justify it with reference to facts and numbers. Along the way, he finds time for all sorts of humourous, cranky or opinionated diversions - for each decade, for example, we get a few particularly strange names picked out, and essays on particular questions that the decade poses (are we justified in calling the various shortlived organisations that preceded or paralleled the National League in the late nineteenth century "major leagues" in terms of quality of play, for instance?). It's a delight to read it cover to cover or just to dip in - it's like having a long conversation during a game with an opinionated eccentric friend who knows an enormous amount and is prone to use his knowledge to launch huge speculations that demand you argue about them. Is there anything sports fans like better than arguing about the game - particularly when the questions can't ever be given a definitive answer? Is Roger Clemens better than Walter Johnson? Nolan Ryan - overrated? What do we think of the save statistic, or of RBI, as indicators of a player's worth? Let the debates commence...