This Digest of Rules of the National Football League has been prepared to aid players, fans, and members of the press, radio, and television media in their understanding of the game. 
It is not meant to be a substitute for the official rule book. In any case of conflict between these explanations and the official rules, the rules always have precedence. 

In order to make it easier to coordinate the information in this digest, the topics discussed generally follow the order of the rule book. 

- Officials' Jurisdictions, Positions and Duties
Responsibilities and positioning of each game official. 

- Definitions
Explanations of football terminology. 

- Summary of Penalties
Descriptions and categories of infractions. 

- Field
Descriptions of the field and the rules regarding it. 

- Ball
Descriptions of the footballs required for each game. 

- Coin Toss
Descriptions of the method of conducting the pre-game coin toss and the choices involved. 

- Timing
The parameters and responsibilities of rules and monitoring of game timing. 

- Sudden Death
The parameters for deciding tied games in sudden-death overtime. 

- Timing in Final Two Minutes of Each Half
Descriptions of time-keeping for the final minutes. 

- Try
Explanations of extra-point procedures. 

- Players-Substitutions
Parameters for player participation and substitutions. 

- Kickoff
Descriptions of kickoff regulations. 

- Safety
Explanations for kicks after safeties. 

- Fair Catch Kick
Explanations for kicks after safeties. 

- Field Goal
Field placement of kicks after field-goal attempts. 

- Safety
The specifications for calling a safety. 

- Measuring
The ball spot used for measurements. 

- Position Of Players At Snap
Requirements for player positioning at scrimmage. 

- Use Of Hands, Arms And Body
Rules and exceptions. 

- Forward Pass
Explanations applying to the passing game. 

- Intentional Grounding Of Forward Pass
Conditions and parameters of this penalty. 

- Protection Of Passer
Rules regarding quarterbacks. 

- Pass Interference
The rights and restrictions of offensive and defensive players in pass coverage. 

- Backward Pass
The conditions and restrictions of laterals. 

- Fumble
Restrictions, spots and advancements of fumbles. 

- Kicks from Scrimmage
Regulations regarding scrimmage kicks. 

- Fair Catch
Parameters for fair catches on punts or kickoffs. 

- Foul on Last Play of Half or Game
Specifics for the final-play situation. 

- Spot of Enforcement of Foul
Four basic spots from where penalties are marked off. 

- Double Foul
The contingencies of double fouls. 

- Penalty Enforced on Following Kickoff
The conditions for penalties being tacked onto the following kickoff. 

- Emergencies and Unfair Acts
Outlining the authority of the commissioner's office and the referee. 

- Unfair Acts
Describes the commissioner's sole authority in dealing with instances outside the accepted boundaries of conduct. 

- Removing Team from Field
The penalties related to teams being removed from the field by any game personnel other than the referee.

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