There's a great book by Jimmy Keenan about his family called "The Lyston's" which traces his family's baseball history from the 1880's to the 1930's. It particularly focuses on his grandfather Jimmy Lyston who played with the Baltimore Orioles in 1921 and he has meticulously researched every team and almost every game his grandpa played in during the 20's and 30's. He spent 2 years in the ESL and that part of the book is very interesting in how the games were played and the fans. Although the time he spent in the Eastern Shore League is just a small part of this big book, it is in my opinion worth picking up. I have read the 2 mainstream books on the league and while very good, neither have a person perspective like Keenan's book.
And for everyone else who just likes a good semi-pro and minor league saga, pick it up!
http://www.keenanbaseball.com/