Firstly, I wanted to draw attention to this book being a rather small book - just over 100 pages. I'll comment on the parts that I've read - and I think this is a pretty good, typical Dover physics book. I wanted something that gave an overview of Linear Vector Spaces and a bit about operators in quantum mechanics, and this book gives a simple, clear introduction to both topics. The part about Vector Spaces and Hilbert spaces is particularly approachable and clear, something often missed in basic undergraduate quantum mechanic text books.
The text is clearly layed out and easy to read. It is clearly an old text reprinted - inside looks as though it was written with type writer - much like some of the old physics books one finds like P. Anderson's Concepts in Solids. I wouldn't pay full-price for the book, as it's rather small and doesn't contain that much, but what it does contain is good.