From publisher blurb:
Folk Magic of the Haven Isles is a role-playing supplement for old school role-playing games. Its focus is on magicians, wizards and magic-users. The book is written for Swords & Wizardry and therefore can be used in all retro-clones and old school role-playing games with little or no work.
But I don't have or play any old school role-playing games. Is it still useful?
Absolutely. It is intended for any fantasy role-playing games to inspire and provide ideas for players and Game Masters alike. If you know what HD and Saving Throws are, you will be easily able to understand and adapt most of the rules-related content in this book.
A Note About The Midderlands
If you know anything about The Midderlands fantasy setting, you will see information within the book that makes it directly usable with The Midderlands setting. It is 100% compatible.
If not, don't worry! You don't need to know anything. There is a glossary that explains what any unfamiliar (mainly geographical) words/terms are. In your own setting, you can just swap out place names.
This 60-page, A5 book includes;
14 Magic-User Sub-classes
16 Magic-User Backgrounds
7 Tomes or Spellbook Ideas
16 Magical Spells
4 Oddities of the Haven Isles