This document discusses lesser-known fighting systems for street defense. It describes two such systems - Keysi Fighting Method and 52 Blocks. Keysi focuses on acting and reacting while defending, using protective arm positions and elbow attacks. 52 Blocks is a primarily defensive style developed in prison to increase awareness, where a single block can save your life. The document was written by Adam Quirk, a criminal justice professional with experience at the FBI and DEA.