This book is dedicated to the memory of Barbara McClintock (1902-1992). In 1983 she was awarded the Nobel Prize in Genetics for the discovery of “jumping genes” (genes that regularly change their positions on chromosomes). In 1944 she served as President of the Genetics Society of America, and in 1945 was President of the National Academy of Sciences. She once confided to me that one reason for her devotion to the study of corn was to combat loneliness.