Paganism and Alternative Beliefs

The Triumph of the Moon: A History of Modern Pagan Witchcraft (1999)
Ronald Hutton

Everything Paganism Book (2004)

What Do Pagans Believe? (What Do We Believe) (2013)
 
Jonathan Black, Mark Booth
 

Triumph of the Moon is the near-definitive account of the new religions that emerged, largely from the UK, in the last century. Hutton is sympathetic but rigorously academic. He has swept away the traditionalist claims of some founders whilst ensuring respect and dignity for practitioners. It is the founding text for understanding the context for any further reading in this field.