For those of us who despise televangelists who claim to heal the sick in the name of God while trolling for donations, who roll our eyes at mediums and psychics who use time-worn “cold reading” techniques to claim they can communicate with the dead, who chortle when tricksters claim they can bend spoons and move objects just by concentrating, the Amazing Randi is something of a hero.

Because the Amazing Randi has been publicly exposing these charlatans for decades now, often through some elaborate trickery of his own.

Directed with style by Justin Weinstein and Tyler Measom, who have done their homework and then some, “An Honest Liar” chronicles James Randi’s amazing (Amazing!) life, from his days as a Houdini-esque escape artist performing on variety shows in the 1950s and 1960s, to becoming such a household name he played himself on an episode of “Happy Days,” through his retirement as a magician at the age of 60 so he could devote all his energies, resources and powers of deception to exposing high-profile faith healers and psychics.

Oh, and Randi was also the executioner who “decapitated” Alice Cooper onstage night after night during Cooper’s “Billion Dollar Babies” tour in the early 1970s. Just had to mention that.

“An Honest Liar” nimbly skips back and forth between recent interviews with the still-spry Randi, now in his 80s, and archival footage of some of Randi’s greatest “Gotcha!” moments.

Randi worked behind the scenes with Johnny Carson’s producers to install some control factors that prevented internationally famous spoon-bender Uri Geller from moving objects without touching them — a huge embarrassment for Geller, and the beginning of a decades-long rivalry between the two. (Randi wrote a book exposing Geller’s methods. Geller filed multiple lawsuits against Randi. In interviews, Geller sounds like a Bond villain as he continues to maintain he has psychic powers. It doesn’t help Geller’s case when we see him selling magic crystal jewelry on QVC.)

Geller seems like a relatively harmless carnival barker compared to the likes of Peter Popoff, one of those evangelical faith healers who could fill arenas with his claims of being able to miraculously cure a variety of ills. Working with surveillance experts, Randi catches Popoff dead to rights. It’s an immensely satisfying moment.

At times though, Randi’s methods are questionable, as when he employed (and perhaps exploited) two young magicians to infiltrate a paranormal research project. Code-named Project Alpha, it was essentially a two-year hoax to expose researchers who were legitimately trying to determine whether psychic powers were real. “An Honest Liar” loses a little momentum as we get bogged down in the minutiae of the elaborate ruse — and we question whether Randi has crossed the line in order to expose others who have crossed the line.

Even more jarring is the dramatic turn of events in the last third of the film, when we learn a stunning truth about Randi’s sometimes partner in exposing hoaxes, and romantic partner of 25 years, Jose Alvarez. Either Randi was aware of a decades-long deception perpetuated by Alvarez — or the great debunker himself was fooled for a quarter-century by the most important person in his life.

Even with my misgivings about some of Randi’s methods, anyone who can challenges faith healers, psychics and mediums who claim a special bond with the dead — and often wins those challenges — deserves a standing ovation. “An Honest Liar” is an honest portrait of just that man.

[s3r star=3/4]

Abramorama presents a documentary directed by Justin Weinstein and Tyler Measom. Running time: 90 minutes. No MPAA rating. Opens Friday at the Music Box Theatre.