I don't know whether Sutherland invented the linked list, but if he did, it had to be before he worked on sketchpad. I attended a lecture about Lisp in 1959 in which McCarthy credited list-processing to IPL-V, whose roots Newell places in 1954. Sketchpad ran on TX 0, which became operational in 1956. My nomination for a triple-threat computer guy is Vic Vyssotsky. A great programmer, he invented the first stream-processing language (BLODI) and bitwise-parallel dataflow analysis. As an architect, he invented the single underlying address space for multics. As a manager, he oversaw the building of and later ran the lab that became AT&T Research. Finally he founded the DEC Cambridge Lab. He was a subtle diplomat, too, who more than once engineered reversals of policy without ruffling feathers. Relative to linked lists, I remember Vic perceptively touting the then startling usage J=NEXT(J).in Fortran. Doug