If you only read one book to understand the reconstructed Anglo-Saxon Heathen religion, let this be that book.
Swain Wodening is a practicing Heathen, and has been for decades. Swain and his brother Eric were instrumental in the founding and development of ASH (Anglo-Saxon Heathenry) in the United States, and his experience shows. While he has done his research, this is not a scholarly book - it is a practical guide to the faith, written to be easily understood. This book contains the background knowledge of the gods and beliefs and practices of ASH and the guidance to live as a Heathen in today's world.
There is so much to be gained from this book that one reading is insufficient.
At least one other review focused on the typos and inconsistent punctuation, and I'd like to address that. Yes, it can be distracting. Try reading this for content, and not as an English composition paper.
Please keep in mind that, like many other "niche publishing" books, this is self-published. Swain isn't making the kind of money from his writings that would allow him to hire a professional editor, and the sales from ASH books are not large enough to interest a big publishing house (yet), with their armies of editors and proofreaders. This is a labor of love, a man sharing his knowledge of his faith. Let content overcome format.
I consider "Hammer of the Gods" to be required reading for anyone interested in the Anglo-Saxon culture and religion, and especially required for those coming into the faith.