Don’t mistake Mark Edward for John Edward. The two men, who are not related, are both professional mediums, men who charge money for their supposed skill at transmitting messages from the dead. But whereas John Edward had a nationally syndicated television show and still plays to large crowds in Las Vegas and across the country, Mark Edward’s biggest gigs were a baby shower at Eddie Murphy’s house and Buddy Hackett’s 70th birthday party.

But what Mark Edward Wilson (he doesn’t use his last name) lacks in professional success, he is trying to make up for in intellectual respectability. In his messy yet fascinating new book, “Psychic Blues: Confessions of a Conflicted Medium” (Feral House), Mr. Edward, 61, comes clean about the tricks that he has used to dupe people since he began working the Los Angeles magic scene in the 1970s. His book is a strange mishmash of self-pity, self-justification and genuine repentance — and a compelling look at the disputed territory where entertainment meets religion, where some practitioners actually think they can practice both at the same time.

There are no new secrets revealed in “Psychic Blues.” Mr. Edward explains techniques to mimic mind-reading and speaking with the dead that have been explained many times before. For example, he describes the old-fashioned preshow screening: work the room before the show, meet a man who says his father’s name was Louis, and then, during the performance, find him in the audience and say right to him, “The name that comes to my mind is Lou. Who is Lou?” Often as not, the mark will forget that he had divulged this information before the show, and will play right into the medium’s hands.

So why write this book? Mr. Edward is staking his claim to belong to a very special subcategory of magicians and mediums: those who both perform their crafts and debunk them. From Harry Houdini to James (the Amazing) Randi and the duo of Penn and Teller, there is a long tradition of magicians who believe that it is their duty to inculcate skepticism in the audience. Because they know the tricks of deception, their thinking goes, they have a unique ability, and a special duty, to teach people how not to get duped.