Contrary to popular belief, there is not a single set of rules for the game of baseball. Major League baseball uses the Offical Baseball Rules (OBR) for their games, as do a great many other leagues, from Little League on up. However, almost all of the leagues that use OBR as a basis for their games, including Major League baseball, have "supplemental" rules that regulate play in their leagues. In addition, there are rules for the game of baseball that are specific to high schools and various college levels. It is imperative that the umpire calling a baseball game know which set of rules, and any "supplemental" rules, are being used for that game.

National Federation of High Schools (NFHS)
    Rule Changes    2006   2007   2008
     Rule Book   (not available on-line)  
    Interpretations   2005   2006   2007   TASO Interpreter 2005 & 2006

National Collegiate Athletic Association (NCAA)
    Rule Changes     2006    2007    2008
      Rule Book
     Interpretations   2007

National Association of Intercollegiate Athletics (NAIA)
      Rule Changes   2006   2007   2008
      Rule Book (NAIA uses the OBR as the basis or their rules, with modifications as shown in the Rules Changes above)

Official Baseball Rules (OBR)
    Rule Changes   2006     2007
      Rule Book

Texas Association of Private and Parochial Schools (TAPPS) (basically NFHS)
    Rule Book

Southwest Preparatory Conference (SPC)
(See NFHS)

Men's Senior Baseball League (MSBL)
     MSBL/MABL Rules
     Rule Book (MSBL/MABL uses the OBR as the bais of their rules, with modifications as shown above)

Summer Ball Tournament Rules
     Wings
      BCS,   Perfect Game,   World Wood Bat (Prater)