Bill Gasarch and Clyde Kruskal, guest blogging for Lance Fortnow, have posted two entries (here and here) on the late Martin Kruskal. Both posts are definitely worth reading, but I especially enjoyed the latter. I just thought that some of you might like reading it too.
By the way, Joseph Kruskal of minimun spanning tree fame is Martin Kruskal's brother. (Historically, the first algorithm for finding a minimum spanning tree was developed by Czech scientist Otakar Borůvka (see Boruvka's algorithm).)