This monograph is written within the framework of the quantum mechanical
paradigm. It is modest in scope in that it is restricted to some obser-
vations and solved illustrative problems not readily available in any of
the many standard (and several excellent) texts or books with solved
problems that have been written on this subject. Additionally a few more
or less standard problems are included for continuity and purposes of
comparison. The hope is that the points made and problems solved will
give the student some additional insights and a better grasp of this
fascinating but mathematically somewhat involved branch of physics. The
hundred and fourteen problems discussed have intentionally been chosen
to involve a minimum of technical complexity while still illus- trating
the consequences of the quantum-mechanical formalism. Concerning
notation, useful expressions are displayed in rectangular boxes while
calculational details which one may wish to skip are included in square
brackets.