Druid Magic focuses mostly on Irish mythology. If the reader isn't familiar with Celtic mythology one will be confused. There is a glossary of Deities, places, and events located in the back of the book. Although that's probably not helpful.
This book is 80% scholar work and 20% Paganism. Or as it is called by the authors "Neopaganism". I have an issue with the word "Neopagnism" because it implies that this is a new kind of Paganism. I believe that Paganism never truly left. Instead required discretion and silence until it was suitable to practice openly again.
Druid Magic is also a reference book. It can be broken into three sections: wisdom of the bards, ovates, and lastly the druids themselves. All the information comes from Celtic literature/folklore that has survived and archaeological evidence. This book is mostly from an anthropological point of view. If the reader is expecting any spells, rituals or fey magic then this book is not adequate. Sutton mention types of exercises one can do, but it's mostly meditation. Not spellwork. The authors believe that spellwork is what witches do. Druids are not witches according to the authors. Agree to disagree. They mention Macha or Bel, but they're just people from history and not Gods. Maya Sutton and Nicholas Mann are just Atheist Pagans in my opinion because they believe in Druidry for the sake of their ancestors. Nothing wrong with this kind of thinking. I prefer scholar writing with my Paganism over new age ideas.
Druid magic has a lot of wisdom through facts. Although I don't understand why for two people who claim to not be witches they sure have a cool piece about sex magick. Ironically enough it's better than any of the "Sex Magick" books I have read. This book also comes with a list of places to visit if you travel to the UK and it is listed by country.
I see many similarities between Celtic and Norse Paganism. This isn't very surprising seeing as the Norse did invade Scotland, England, and Ireland. They also share a similar code of "conduct" in honour above all, knowledge, and paying homage to ancestors. Someone not honouring their word or obligations was a serious offense.
All in all this was a very insightful book.