I was 13 when I read "Ball Four" for the first time. That was in '75 and I have re-read it several times as an adult. It's easily the best sports book I've ever read. Bouton captured the alternating feelings of insecurity and elation that pitchers experience in a way that still rings true in spite of the many ways baseball has changed over the years.
I still make a point of re-reading some of my favorite passages from "Ball Four" every year in late March. This is more of a tradition than a necessity now that I can read about baseball 365 days a year. Back in the 70s and 80s reading "Ball Four" was a great way to reorient my brain away from college basketball and toward baseball. Bouton did a great job of putting the reader inside the head of a major leaguer.
One of the best things about "Ball Four" has nothing to do with baseball. It is an excellent chronicle of the different ways a diverse group of young men handled a very stressful job amid the cultural upheaval of the late 60s.
I hope Jim is comforted by the knowledge that his observations about sports and more importantly, human nature, have influenced many readers. Hang in there, Jim... and don't forget to "Smoke 'em inside."