The QM class I originally took used Liboff. I could barely understand a word of it and ended up dropping the class. Later I found the Shankar book and was thril

The QM class I originally took used Liboff. I could barely understand a word of it and ended up dropping the class. Later I found the Shankar book and was thrilled with it by comparison. I'm not a math whiz though, so lack of "rigor" on a first pass is just fine by me. For an intro level text for the average person, I found Shankar was one of the few accessible ones. Haven't read Griffiths yet so I can't comment on it.