Leibnitz, Gottfried Wilhelm  (1646-1716),
great mathematician and philosopher, planned to write
an "Art of Invention" but he never carried through his
plan. Numerous fragments dispersed in his works show,
however, that he entertained interesting ideas about the
subject whose importance he often emphasised.  Thus, 
he wrote: "nothing is more important than to see the
sources of invention which are, in my opinion, more
interesting than the inventions themselves."