This is my new favorite baseball book ever. (Literally.)
It's about the players. It's also sort of about the rankings, and sort of not. Posnanski mostly ignores methodological issues until ~90% of the way through the book. His explanations for the rankings, when they come, are steady and reasonable, but also involve a lot of shrugging his shoulders. This all reminds me of the economic/philosophical problem of interpersonal comparisons of utility: there's basically no way to do it right, but not doing it at all is also obviously not right. The Baseball 100 gets this balance basically right, even (or perhaps especially) when the ratings look most like a cop-out.
So, for example, Jackie Robinson is in 42nd place; he wore number 42. How much more can be said? By career MLB WAR, he's 103rd or so among position players. By other standards, he's an easy #1. The more I think about Posnanski's approach, the more I like it: Put him in the top half, write a beautiful and insightful portrait, make it clear you're honoring the number, and get on to #41.
A major success of the book is keeping the reader's attention on the portraits. There's a lot here about family culture and some local culture, but not many sweeping claims about American culture (no "Wade Boggs was a product of the sixties"). Posnanski earns your interest and focus by making the people in the book pop, and he doesn't cash it out for a cheap or boring point about politics or culture. (Of how many recent books could that be said?)
Two themes run through the book: parental influence and the shame of baseball's segregated past. As for the former: Posnanski writes beautifully about childhood. As for the latter: what else can he do? In a book that's at all about rankings, not talking about segregation a lot would be like talking about 2020 college football without talking about COVID a lot.
If anything, I think Posnanski's "take the best guesses you can with all the evidence you have" approach should have taken him even farther. Charlie Gehringer really comes ahead of Martin Dihigo, Cristobal Torriente, and Turkey Stearnes?
This book made me think often of Chuck Klosterman's But What if We're Wrong?, which is the best treatment I've seen of the strangeness of cultural influence. Besides the top 100 themselves, there are anecdotes involving so many long-ago MVPs and statistical standouts. Many of those players' names ring loud bells in my head and, I'm pretty sure, others'. They've kept their portions of fame. Many others are absolute blanks to me. I have no real idea what accounts for this. Posnanski, like Klosterman, does a great job laying out mysteries of influence, not just in cases like Arky Vaughan (why is such a great player so obscure?) but also in cases like Roger Clemens: Why isn't it a bigger deal that he threw a bat at Mike Piazza in the World Series? How exactly will Clemens be remembered?
Posnanski's answers aren't always satisfying, but maybe there aren't answers to be found; maybe influence is just that deeply arbitrary. What's more important is that Posnanski has the ability to paint portraits so well and freshly that he's in a position to see those questions in the first place.