Ernst Theimer was, in my humble opinion, one of the two contemporary "crossword boundary stretchers" of our time (along with Charles Deber). Figuring out a Theimer theme often requires forgetting everything you know about crosswords or letting one's mind wander aimlessly in thought. His puzzle "Start Making Tarts" must hold the record for most theme answers in one Sunday NYT puzzle. His fourteen career Sunday puzzles (available as a zip file) are a perfect fit for Litzmas 2001:
Ernst Theimer passed away July 2, 1994 at the age of 83. The NYT carried an obituary on July 7, 1994 of which I excerpt a portion here: "...he was devoted to intellectual games and was a constructor of crossword puzzles, about 30 of which were published by The New York Times. When his puzzles were published, hundreds of readers often phoned or wrote letters expressing their bewilderment at their intricacy."