Math Proofs Demystified
Stan Gibilisco
McGraw-Hill
This book is too elementary for advanced students (upper undergraduate, graduate or above), * even non-math majors *, and even if you have never taken a course on math proofs or logic.  You won't find much in this book that you haven't already gotten from other sources or learned "the hard way".  

However, at the high school or lower undergraduate level, or for an extremely non-mathematically oriented person, I recommend it since it contains information that you're not likely to find in other books at that level, not only about proofs but also basic logic.  

As for the "Demystified Series", I have another book that is great.  This one was a disappointment.