Unless you are VERY knowlegable about linguistic terminology (which the author uses very freely -- assuming that the reader will know what he means) and/or are exceptionally talented at learning languages and/or are using this book in a classroom with a native-speaker instructor, you are not likely to make much headway with it.
Spoken Cree is not a self-teaching book. It's intended to be used in a classroom with a teacher who can explain many of the more complicated aspects of the language and offer extensive opportunities for practice. The writing style is dense; explanations inadequate or overly complex. Add to that the fact that Cree is, of course, not an indo-European language and has a structure completely different from any language you might already be familiar with -- the result (for the self-tutored pupil) is rapid and complete frustration.
The book is also apparently supposed to come with a CD or tape. The discussion of how the language is pronounced is minimal at best, and the use of transliterated Cree through-out the book doesn't really help matters. But there is no CD or tape, so pronunciation remains a mystery.
Finally, while the book IS titled "Spoken Cree" and so focuses on conversation and grammar, I would have welcomed at least a little bit of written Cree. Cree uses a syllabery (each 'letter' is a full syllable) rather than an alphabet, which was created in the 19th century. As such, it is 100% logical and fairly simple. I might have enjoyed the book more if the author had first spent a few chapters at the start teaching the learner to read Cree, and then used it through-out the boook, rather than relying on a cumbersome transliteration and ... when all is said and done, leaving the learner who manages to somehow get through all 18 units, still unable to either read or write. (The syllabery is introduced briefly at the end of the book, but the learner is given little chance to use it or see it in use.)