Passed on to me by my man Sammy.
Having been alerted to the excesses of one-neat-trick books by all of my If Books Could Kill listening, I went into this with a decent degree of suspicion--all the more because Ryan grew up as a sportswriter (she wrote the essential Little Girls in Pretty Boxes, which feels all the more necessary and forward-looking by the minute), and in general people going out-of-field can be especially susceptible to the disease of finding an article from some psych journal and stretching it to cover everything.
So the modesty of the analysis and claims here came as a reassuring and welcome surprise. Ryan talks to sociologists and social psychologists and neuroscientists and Stanley McChrystal, and noted glue guys like Jonny Gomes and Hunter Pence and, briefly, Aubrey Huff, famous anti-glue guys like Jeff Kent and even, eventually, Barry Bonds (who lived in...Larkspur? someplace where there are ferries in what sounds like Marin), after several years' persistence, and Michael Lewis and Theo Epstein, because of course, as well as baseball lifers like Jim Leyland and Tony La Russa, and she listens respectfully to all of them. End result? Chemistry is probably real (saddest/funniest note is the social psychologist who had her grad students spend WEEKS coding player interactions on video to determine how they might affect quality of play, only to conclude that there wasn't enough evidence and no points of comparison for all of this data), but not everything, since also being really good at your sport also matters kind of a lot. She cites a couple of studies proving that too many to-rank types can be counterproductive (wondering what Man City's recent fortunes say about this--or that Soccernomics stat that, as of the last version I read, which is maybe two editions ago, 92% of a European club's results are attributable to payroll, which maybe by implication suggests how much weight we might assign to...intangibles), which returns to the point that stats, by themselves, suggest most but not all of what a team can do.
Her central narrative hub is the '89 Giants, who for most of the season hit on the right balance of all of these things, from detente between the born-agains and carousers to figuring out how to make sure Kevin Mitchell felt appreciated, given his own insecurities--which clearly worked that year, as he won MVP. In that sense, maybe the meta-story here is about the rise in understanding of male subjectivity/sensitivity, the lesson that numbers can't and shouldn't be absolutely everything, and that men need to feel appreciated and loved and cared for to succeed, even if a lot of that comes out as taunts and teases and kangaroo courts.