When William James (http://en.wikipedia.org/wiki/William_james) went to the University of Edinburgh in 1901 to deliver a series of lectures on ‘natural religion’, he defined religion as ‘the feelings, acts, and experiences of individual men in their solitude, so far as they apprehend themselves to stand in relation to whatever they may consider the divine’. Considering religion, then, not as it is defined by – or takes place in – an institutional fashion in the churches. Rather as it is felt in everyday life. James undertook a project that stands not only as one of the most important texts on psychology ever written, not only as a vitally serious contemplation of spirituality, but for many critics one of the best works of nonfiction written in the 20th century.
Reading The Varieties of Religious Experience (1902), it is easy to see why. Applying his analytic clarity to religious accounts from a variety of sources, James elaborates a pluralistic framework in which ‘the divine can mean no single quality, it must mean a group of qualities, by being champions of which in alternation, different men may all find worthy missions’. It’s an intellectual call for serious religious tolerance – indeed, respect – the vitality of which has not diminished through the subsequent century. It has been the fountainhead of an entire academic industry of research into religion as an aspect of human culture, and of its psychology.
Follow up with Richard Eyre’s The Long Search (1979) (http://www.amazon.co.uk/Long-Search-Ronald-Eyre/dp/0006253733/ref=sr_1_1?s=books&ie=UTF8&qid=1388340183&sr=1-1&keywords=the+long+search) based on a TV series in the 1970s about religious experience around the globe.
If really intrigued by comparative religion, then reach for Momen, Moojan (2009) Understanding Religion: A Thematic Approach Oxford: Oneworld Publications. ISBN 978-1-85168-599-8 (http://www.amazon.co.uk/Understanding-Religion-Thematic-Moojan-Momen/dp/1851685995/ref=sr_1_1?s=books&ie=UTF8&qid=1388353437&sr=1-1&keywords=9781851685998)
576 pages in Penguin Classics paperback edition
ISBN 978-0140390346
William James