I know Harry Nelson from our mutual attendance at the annual International Puzzle Party.
Some of his puzzles:
Gravity Well - I was able to take it apart, but could never put all 3 pieces back together. I still have no idea how I disassembled this. This puzzle was made in China for Bits & Pieces and I can imagine that at their factory, there was only 1 person who put them together.
Lunar Lockout - brilliant design. Another version was called Pike's Peak. A lot of puzzle apps have incorporated some of this game's features. One that comes to mind is Fling!
Cool Circuits - I have not played this, but want to!
Click on the link at the top to see a chess puzzle that took him 10 years to design. How crazy is that?