Rabkin claimed that his early classical violin studies and exposure to the rigors of classical music helped him to "think abstractly". Perhaps so, as his work often featured unusual and found materials with no tangible value that he assembled into three-dimentional wall hangings and boxes as well as collage-like works. He was a member of the American Abstract Artists group and served as its president from 1964-78. He and his wife also assembled a large collection of American folk art which they donated to the American Folk Art Museum.