How do creative geniuses generate so many alternatives and conjectures? Why are so many of their ideas so rich and varied? How do they produce the “blind” variations that lead to the original and novel? A growing cadre of scholars are offering evidence that one can characterize the way geniuses think. By studying the notebooks, correspondence, conversations and ideas of the world’s greatest thinkers, they have teased out particular common thinking strategies and styles of thought that enabled geniuses to generate a prodigious variety of novel and original ideas.