Books like Rules for Vanishing

In Ian Fleming's James Bond novels and the derived films, the 00 Section of MI6 is considered the secret service's elite. A 00 is a field agent who holds a licence to kill in the field, at their discretion, to complete any mission. The novel Moonraker establishes that the section routinely has three agents concurrently; the film series, in Thunderball, establishes a minimum number of nine 00 agents active at that time.