Entry Source: The Complete James Bond Movie Encyclopedia by Steven Jay Rubin

Bond's longtime nemesis and the head of the Special Executor for Counter-Intelligence, Terrorism, Revenge, and Extortion (S.P.E.C.T.R.E.)—an enormous criminal organization introduced in Ian Fleming's Thunderball novel and based on a film story created by Jack Whittingham, Kevin McClory, and Fleming. S.P.E.C.T.R.E. and Blofeld are also featured in the novels On Her Majesty's Secret Service and You Only Live Twice.

In the movies, Blofeld is first featured with his back to the camera in From Russia with Love (portrayed by Dr. No veteran ANTHONY DAWSON). Eric Pohlmann is Blofeld's voice in both From Russia with Love and Thunderball.

He makes his on-camera debut in You Only Live Twice, with Donald Pleasence in the role, complete with an incredible scar supplied by the makeup department. Quoting film critic Alexander Walker, James Bond in the Cinema author John Brosnan wrote, "Pleasence resembles ‘an egg that had cracked on the boil.’"

Hatching a scheme to start World War III on behalf of the Red Chinese, Blofeld in You Only Live Twice builds a secret rocket base in-side a dormant Japanese volcano. From this enormous conclave, he launches his Intruder rocket—a jaw-opening spaceship that captures Soviet and American capsules. When Bond (SEAN CONNERY) invades the base with the help of an army of Ninja warriors, Blofeld escapes to appear in the next film, On Her Majesty's Secret Service, in the guise of Telly Savalas.

This time Blofeld is sequestered in the Swiss Alps, posing as a world-famous allergist. In reality, he is developing a terrifying germ warfare strain that will destroy the agriculture and livestock of the world's leading nations. His agents are young female allergy victims who have been brainwashed to perform their deadly deed. Once again, Bond (GEORGE LAZENBY) comes in to mess up the works. During a climactic chase in the bobsled run, Blofeld appears to have been killed when his skull is cracked by an overhanging branch, but he returns in the climax with Frau Irma Bunt (ILSE STEPPAT) to murder Bond's bride, Tracy (DIANA RIGG).

In Diamonds Are Forever, Blofeld is portrayed in a very sophisticated manner by Charles Gray. With his smart uniforms, cigarette holder, and sparkling quotations, this Blofeld is the most fantastical of them all. His plot is nothing less than nuclear blackmail from outer space, thanks to his diamond-powered laser satellite. Blofeld gets trapped in his own bathosub, with Bond (SEAN CONNERY) controlling the crane that lowers it into the water. The sub later explodes, but Blofeld's body is never found or seen.

Although he was never identified by name in the credits, a bald-headed, wheelchair-bound, beige-uniformed Blofeld appears in the For Your Eyes Only teaser with his trademark white cat. Snared by Bond's (ROGER MOORE) helicopter skid, he's deposited in the nearest industrial smokestack, which would appear to be his final and utter demise.

In fact, it would take the rival Bond group in Never Say Never Again to resurrect the S.P.E.C.T.R.E. chieftain in the guise of actor Max Von Sydow. Like the never-fully-seen Blofeld in the early 007 films, this one simply announces the latest extortion plan and keeps in touch with his field commander, Largo (KLAUS MARIA BRANDAUER).

Blofeld was supposed to have been featured as the key villain in The Spy Who Loved Me, but because of threats from Thunderball producer Kevin McClory, who claims all rights to Blofeld and the S.P.E.C.T.R.E. organization, producer Albert R. Broccoli had screenwriter Richard Maibaum change the character to the purely independent villain Karl Stromberg (CURT JURGENS).