Calculus Demystified
Steven G. Krantz
McGraw-Hill
I think all you need to know about this book is the intro to limits.  Why not use a simple continuous function with a single definition to introduce the idea?  What can possibly come from using a function that has different definitions depending on the range of x, except adding an unnecessary detail for the reader to weed through?  It almost seems that the author is intentionally making it sound complicated to convice the reader that he (the author) is so brilliant that he (the author) can't understand how the reader isn't able to connect the dots, which he (the author) has made unnecessarily difficult to connect.  Examples of this unnecessary obfuscation is found in spades in this book.