The Official Professional Baseball Rules Book governs all aspects of the game of Major League Baseball beyond what happens on the field of play. There are a number of sources for these rules, but they all ultimately are sanctioned by the Office of the Commissioner of Baseball. Examples of these rules are the Rule 5 draft (so-named for the applicable section of the rule book) and the injured list.
Other examples include:
the 5/10 Rule whereby players who have been with a club for 5 consecutive years and have been a major league player for 10 years cannot be traded without their consent.
the roster list rules (active and expanded rosters) which also determines who is eligible to play for a team in the playoffs and World Series
tie-breaking rules for deciding which teams go to the playoffs
implementing/enforcing the expanded playing rules issued to umpires which goes into much greater detail than the official baseball rules of play. These rules are described in the Umpire's Manual.
The Official Professional Baseball Rules Book is organized into the following sections:
The below sections enumerate the numbered Major League Rules, both before and after Major League Baseball reorganized the minor leagues in advance of the 2021 season, as multiple rules were changed at that time.
As most rules do not state what the penalty is for a violation, broad discretion is granted to the Commissioner of Baseball via Rule 50, "Enforcement of Major League Rules", which specifies "action consistent with the commissioner’s powers under the Major League Constitution".