'The careful and comprehensive treatment given in the book, utilizing a wide range of modern analysis (...) is accompanied by equally careful discussion of the physics involved, so that it should be accessible and useful to a wide range of mathematicians, physicists, to whom it is primarily directed.' Mathematical Reviews (1986) '...the best and most comprehensive exposition that has appeared so far. ... ...I am tremendously impressed by individuals who have mastered large parts of both the physics of modern quantum theory and the associated rigorous mathematics; Exner is one of these individuals. I heartily recommend his book.' Foundations of Physics, 15 (1985)