This really is a nice book: sentences and selections are arranged according to the chapter of Wheelock's Latin, going along with the pace of the textbook's difficulty and introduction of vocabulary.
First off: NOT FOR LATIN NEWBIES! This is a very fast-paced course. If you have no previous Latin experience, you should start with another text. It's called a Primer of Ecclesiastical Latin, and technically it is, but it is not good for use as a primer for learning Latin--so caveat emptor!