Leo Dillon and Diane Dillon are/were American illustrators of children's books and adult paperback book and magazine covers. One obituary of Leo called the work of the husband-and-wife team "a seamless amalgam of both their hands". In more than 50 years they created more than 100 speculative fiction book and magazine covers together as well as much interior artwork. Wikipedia*
On the C-SPAN Networks:
Diane Dillon has one video in the C-SPAN Video Library; the first appearance was a 2012 House Committee.