Paul Erdos: The Oddball's Oddball

He would appear on the doorstep of fellow mathematicians without warning--a frail, disheveled, elderly man, hopped up on amphetamines and wearing a ratty raincoat--and announce, in a thick Hungarian accent, "My mind is open." For a day, or a week or a month, the man or woman who answered the knock would have to take nonstop care of this helpless guest who couldn't figure out how to cut a grapefruit or wash his underwear--and in return would be permitted the exhausting, exhilarating experience of following the thought processes of Paul Erdos, the most prolific and arguably the cleverest mathematician of the...