Felix, Bond's Langley brother

Felix Leiter is a reoccurring character in James Bond novels and movies. One of the tightest moments of drama in the current Bond, Quantum of Solace, unfolds between Bond (Daniel Craig) and Leiter (Jeffrey Wright reprising his role from Casino Royale) where they briefly meet in a South American bar, exchange a few quaint words and then Leiter tells Bond to run, as in he's got half a minute before the military raids the joint. In this case there's a grey area of allegiance since Leiter's CIA partner wants to kill Bond.
Leiter appeared in the first feature length Bond Dr. No, played by Jack Lord (forever associated as McGarrett in his 70s role from TV's Hawaii Five-0). Leiter subsequently turned up in Goldfinger, played by Cec Linder, and Thunderball, played by Rik Van Nutter, a rock and roll name if we ever heard one. Bond's American doppelganger appears in the last Connery EON Production Bond, Diamonds Are Forever, with Norman Burton as Leiter and then in the non-EON Never Say Never Again, bigger and rougher and played by Bernie Casey.
The Roger Moore Bonds kicked off with David Hedison (perhaps best known as the second lead behind Richard Baseheart in Voyage to the Bottom of the Sea) as Leiter, who otherwise remains absent from the rest of the Moore efforts. But Leiter's back in the two Timothy Dalton Bonds, first in The Living Daylights played by John Terry, and then, and undoubtedly the secret agent's most important appearance, in Licence to Kill with Hedison reprising his role from Live and Let Die. For Licence to Kill Leiter has switched to the DEA and the murder of his wife and his abduction, while on their honeymoon, sets the film's plot in motion. In a sequence that Ian Fleming wrote in one of the Bond novels, Leiter gets his leg eaten by a shark while being tortured by the villains. And with Benicio Del Toro and Robert Davi as baddies Licence to Kill has plenty to offer. Another CIA ally turns up in Licence to Kill, Pam Bouvier played with tremendous assurance by Carey Lowell. Her personality is duplicated but not equaled by Halle Berry as Jinx in Die Another Day.
Since Leiter was wounded he was not brought back for the Brosnan Bonds, although there is the character of CIA agent Jack Wade played by Joe Don Baker in Goldeneye and Tomorrow Never Dies. Baker had also played a corrupt general in The Living Daylights.
Wright brings a flair for the mysterious to his current re-booted portrayal of Leiter. After all we're in another century ruled by knowledge rather than secrets and the spy business has to acclimate to the times.