Here's some books covering 19th century baseball that are available at Amazon.com. Almost all are priced right around $10.00. There's a lot of good deals that may not last long.

Links listed in roughly chronological order:

General histories of the early game:
https://www.amazon.com/Inventing-Bas...1Q17FXTKSPPFEW
https://www.amazon.com/Baseball-Gard...86GYZ5AYZ3WE1V
https://www.amazon.com/Baseballs-Fir...E1RB1NE6RCJ6K2
https://www.amazon.com/Baseball-Earl...V25QYRD6JKP2WM
https://www.amazon.com/Base-Ball-Pio...86GYZ5AYZ3WE1V
https://www.amazon.com/Base-Ball-Fou...86GYZ5AYZ3WE1V
https://www.amazon.com/Playing-Keeps...86GYZ5AYZ3WE1V
https://www.amazon.com/Blackguards-R...uards+baseball
https://www.amazon.com/Days-Wee-Will...86GYZ5AYZ3WE1V

Bios
https://www.amazon.com/Cap-Anson-Gra...BYQ5YW7CTF09ZF
https://www.amazon.com/Big-Dan-Brout...86GYZ5AYZ3WE1V
https://www.amazon.com/Roger-Connor-...2HGSNGN1PNQ5BW
https://www.amazon.com/Buck-Ewing-Bi...rds=buck+ewing
https://www.amazon.com/Big-Sam-Thomp...EMEYRGA32TTM3Q
https://www.amazon.com/Sliding-Billy...2HGSNGN1PNQ5BW