Chris Hadnagy
Author and consultant who made social engineering its own speciality within penetration testing.
Hadnagy's book Social Engineering: The Art of Human Hacking (2010) was one of the first attempts to systematise what Kevin Mitnick had done by ear: pretexting, information gathering, influence techniques. His company, Social-Engineer, sells phishing campaigns and phone-based tests to firms that want to know how easily reception will wave in a "technician".
From 2010 he ran the Social Engineering Village at DEF CON, including a contest in which participants phoned real companies in front of an audience. In 2022 DEF CON banned him, citing code of conduct violations, which he disputed. He also founded the Innocent Lives Foundation, which uses OSINT to help police track down child abusers.