Instruct: Classify Amazon reviews into positive or negative sentiment
Query: A good book with a mortal sin

This is a five stars book with a mortal sin.The book is a good introduction to functional analyses with quantum mechanics serving as motivation for definitions and theorems.It is very good for physics students that have already had a good course on quantum mechanics. Since it is intended to be a book to be used as described it is incomplete as a functional analysis book. Now the mortal sin: the author presents spectral theory using projection operators.This is fine. However to neglect the conection with the continuos spectrum will surely repel the intended audience. There are other books that do not do this and therefore are to be prefered.An old one is by Friedman( Lectures on applications oriented mathematics) . A new one is by Zeidler(Applied functional anlysis: applications to mathematical physics)