I last wrote about Peak nearly ten years ago. His brief Wikipedia entry is here. Some information regarding his later years' technique when he was doing a good deal of airbrush work is here.
In 2009 illustration maven David Apatoff wrote about Peak here, mentioning:
"But in the 1960s, Peak caught fire and began turning out radically different work. His line work had roots in the Viennese Secessionist movement (particularly Schiele and Klimt) and in the great Rene Bouche, but Peak's hot, fluorescent color combinations were unprecedented; his extreme angles, cinematic style, and space age dynamism were blazingly original....
"Peak's salad days in the 1960s were a remarkable, vibrant period, but he was too hot not to cool down. As Peak matured, he remained commercially successful but his innovations came fewer and farther between. He had a lucrative career making movie posters that seem to me to be repetitive and uninspired, the type of art that might be sold on vacation cruise ships."
I'm not as negative as Apatoff with respect to Peak's movie poster era because much of what he did was striking. But it was repetitive due perhaps to a need to preserve a stylistic image helpful to his career and perhaps because film company publicity departments expected him to use his signature poster style.
And I agree with Apatoff that Peak's best work was done during the pre- movie poster years. Examples from around that time are presented below.