CNN Editorial Research provides a look at the life of John Brennan, former director of the CIA.
Brennan was considered a candidate for CIA director after President Barack Obama's election in 2008, but dropped out due to criticism for supporting enhanced terrorist interrogation techniques.
In 1980, Brennan joined the CIA's Directorate of Operations as a Career Trainee.
Author's summary: John Brennan, former CIA director, has a diverse background in education and intelligence.