The most up-to-date rule book for the National Hot Rod Association can be purchased from the NHRA's official website at NHRA.com. You must have a membership with the NHRA to view the organization's rulebook.
Other NHRA publications dealing with the rules and regulations of the sport are also available on its website, and you can view them without a membership. The NHRA has also posted rulebook amendments from the previous year to the following season and the general regulations regarding the specifications of race cars in PDF format.
In addition to the NHRA rulebook, you can view associated leagues' rulebooks, such as NHRA Youth Racing and the Harley-Davidson Drag Racing Series.