Why is it that some writers struggle for months to come up with the perfect sentence or phrase, while others, hunched over a notepad or keyboard deep into the night, seem unable to stop writing? In The Midnight Disease: The Drive to Write, Writer's Block, and the Creative Brain (Houghton Mifflin, January), neurologist Alice W. Flaherty explores the hows and whys of writing, revealing the science behind hypergraphia -- the overwhelming urge to write...