Well, this book contains exactly what it states on the cover: a bunch of different mandolin chords with different voicings (or "patterns" if you use that word for chord grips). You need to know your songs and use this book for reference when you get stuck or can't find your way to a specific chord. Just as with any other chord book.
Once you take on the mandolin as a new instrument, this little book comes in handy. It really helped me a lot to find my way around the instrument. It's clear, it's simple to use and it gives you everything you need for the beginning until the intermediate stages.