From here:
http://baseball1.com/statistics/readme57.txt
Code:
2.1 MASTER table
lahmanID Unique number assigned to each player
playerID A unique code asssigned to each player. The playerID links
the data in this file with records in the other files.
managerID An ID for individuals who served as managers
hofID An ID for individuals who are in teh baseball Hall of Fame
birthYear Year player was born
birthMonth Month player was born
birthDay Day player was born
birthCountry Country where player was born
birthState State where player was born
birthCity City where player was born
deathYear Year player died
deathMonth Month player died
deathDay Day player died
deathCountry Country where player died
deathState State where player died
deathCity City where player died
nameFirst Player's first name
nameLast Player's last name
nameNote Note about player's name (usually signifying that they changed
their name or played under two differnt names)
nameGiven Player's given name (typically first and middle)
nameNick Player's nickname
weight Player's weight in pounds
height Player's height in inches
bats Player's batting hand (left, right, or both)
throws Player's throwing hand (left or right)
debut Date that player made first major league appearance
finale Date that player made first major league appearance (blank if still active)
college College attended
lahman40ID ID used in Lahman Database version 4.0
lahman45ID ID used in Lahman database version 4.5
retroID ID used by retrosheet
holtzID ID used by Sean Holtz's Baseball Almanac
bbrefID ID used by Baseball Reference website