If magic is your thing then this is the book you need. All sorts of new qualities for your witch, wizard or mad scientist. Spells from the fist six season of Buffy and revised sheets for magic using characters.

Much like the Slayers Handbook, which focused on slayers this book takes a character type and expands it - namely practitioners of magic. Presents the usual mix of character and setting options with a focus on magic. Also presents new archetypes. Not strictly necessary, but well worth the money if you have interest in expanding magic in your Buffy game.