K. K. Ruthven 
Myth [PDF ebook] 

First published in 1976, this book provides a helpful introduction to the study of myth as a concept and its relationship to literature. It examines historically some of the leading theories concerning the nature and origins of myth and, with reference to a wide variety of texts, illustrates the relevance of these theories to literature. It also considers the different ways in which myths have been perceived over time, both positive and negative, and the effect this has had on the production of new mythologies. It concludes with an assessment if the problems created by the presence of myth in literature and its use as a tool of literary criticism.