An excellent follow up to his Pulitzer winning "Goedel, Escher, Bach: an eternal golden braid" Written in an essay format Dr Hofstadter delves into everything from Rubik's cube to short biographies of science greats - and all these wide ranging essays are organized into a coherent, intricately organized order that somehow finds a connection to everything. Written for a popular audience Hofstadter is always searching for and asking even deeper philosophical questions which often touch upon the supernatural.