Pretty much what Thalaba said. A large portion of the book is usable simply with the Big Gold Book. If you use Basic Magic, or the new book, you'll get more out of it as there are new spells and options for those systems as well.
The enchantment stuff also is usable with the BGB. I created a Ritual magic system that is a basic version of the rules from Basic Magic but with a vastly expanded selection of ritual magic.
And of course there are the enchanted items that work straight with the BGB.
Hope that helps.