Uncrossed Knight Paths is NP-complete  
   Draft of a paper by Dominic Mazzoni and Kevin Watkins proving that finding paths in Twixt (i.e., whether it is still possible to win) is NP-complete.
   http://www.mathematik.uni-bielefeld.de/~sillke/PROBLEMS/Twixt_Proof_Draft

Mark Thompson's Twixt page  
   Printable board diagram, brief history of the game, suggested variant, links.
   http://www.flash.net/~markthom/html/twixt.html

MindZine: TwixT and Quarter-board  
   By David Bush. Introduction and course in basic game strategy.
   http://www.msoworld.com/mindzine/news/proprietary/twixt/twixt1.html

Twixt  
   A review of the 3M Bookshelf Game Twixt (1963). Twixt is a three dimensional version of an old pen and paper game. The object of the game is to build an uninterrupted "bridge" from one end of the board to the other.
   http://ourworld.compuserve.com/homepages/Dennis_Matheson/3m20.htm

Programs to Play Twixt  
   Collection of information on game playing programs. Also features T1.
   http://www.johannes-schwagereit.de/Twixt.html