Robert Graves (1895-1985) was a British poet and author, probably best remembered for his I, Claudius novels written in the mid 1930s and later dramatized by the BBC in 1976. His 1948 work The White Goddess - a speculative account of Pagan myth and poetry - has been very influential in the growth and development of Wicca, which was founded in the same year.
The two volume "Greek Myths", published by Penguin in 1955 (revised 1960), is considered a definitive text on the subject.