The Sacred Mushroom and the Cross

The book was first published in 1970 but the author had written a couple of books on the Dead Sea Scrolls previously since he was on the team of scholars which first studied them until he had a falling out. Rather than a book about drugs this one is more a look at the origins of Christianity and drew quite a deal of criticism from Catholicism predictably enough.
It isn't an easy read but isn't meant to be. It asks provocative questions and provides interesting information to try and answer them but is unable to offer much in the way of definite conclusions. I am inclined more to the Mr. and Mrs. Jesus hypotheses put by 'Grail scholar' Michael Baigent.