Puthoff was born in Chicago, Illinois. He received his BA and MSc in electrical engineering from the University of Florida.^[2] In 1967, Puthoff earned a Ph.D. in electrical engineering from Stanford University with a thesis on the topic of the stimulated Raman effect in lasers.^[3][4] He then worked on tunable lasers and electron beam devices, and co-authored (with R. Pantell) Fundamentals of Quantum Electronics (Wiley, 1969), published in English, French, Russian and Chinese. Puthoff published papers on polarizable vacuum (PV) and stochastic electrodynamics.

He took an interest in the Church of Scientology in the late 1960s and reached what was then the top OT VII level by 1971.^[4] Puthoff wrote up his "wins" for a Scientology publication, claiming to have achieved "remote viewing" abilities.^[5] In 1974, Puthoff also wrote a piece for Scientology's Celebrity magazine, stating that Scientology had given him "a feeling of absolute fearlessness".^[6] Puthoff severed all connection with Scientology in the late 1970s.^[7]

In 1985, Puthoff founded a for-profit company, EarthTech International in Austin, Texas. At about the same time, he founded an organization, Institute for Advanced Studies at Austin (IASA), which he directed.^[8] IASA, funded by anonymous donors, pursues ideas Puthoff finds interesting related to energy generation and propulsion.

Puthoff and EarthTech were granted a US Patent^[9] in 1998, with claims that information could be transmitted through a distance using a modulated potential with no electric or magnetic field components. While "the invention does appear to rest on solid, albeit somewhat obscure, physics principles", the case is used for educational purposes in patent law where "the examiner failed to make a prima facie case for inoperability or lack of enablement".^[10] According to the Wisconsin Law School case study, "The lesson of the Puthoff patent is that in a world where both types of patents are more and more common, even a competent examiner may fail to distinguish innovation from pseudoscience."

In the 1970s and 1980s Puthoff directed a program at SRI International to investigate paranormal abilities, collaborating with Russell Targ in a study of the purported psychic abilities of Uri Geller, Ingo Swann, Pat Price, Joseph McMoneagle and others, as part of what they called the Stargate Project. Both Puthoff and Targ became convinced Geller and Swann had genuine psychic powers,^[11][12] however Geller had employed sleight of hand tricks.^[13]

Uri Geller was studied by Russell Targ and Puthoff at the Stanford Research Institute (SRI). Targ and Puthoff declared to have demonstrated that Geller had genuine psychic powers, though it was reported that there were flaws with the controls in the experiments and Geller was caught using sleight of hand on many other occasions.^[14][15] According to Terence Hines:

Geller turned out to be nothing more than a magician using sleight of hand and considerable personal charm to fool his admirers. The tests at SRI turned out to have been run under conditions that can best be described as chaotic. Few limits were placed on Geller's behavior, and he was more or less in control of the procedures used to test him. Further, the results of the tests were incorrectly reported in Targ and Puthoff's Nature paper.^[16]

Psychologists David Marks and Richard Kammann attempted to replicate Targ and Puthoff's remote viewing experiments. In a series of thirty-five studies, they were unable to replicate the results. While investigating the procedure of the original experiments, Marks and Kammann discovered that the notes given to the judges in Targ and Puthoff's experiments contained clues as to which order they were carried out. Examples included referring to yesterday's two targets, or the inclusion of the date of the session written at the top of the page. They concluded that these clues were the reason for the experiment's high hit rates.^[17][18] Terence Hines has written:

Examination of the few actual transcripts published by Targ and Puthoff show that just such clues were present. To find out if the unpublished transcripts contained cues, Marks and Kammann wrote to Targ and Puthoff requesting copies. It is almost unheard of for a scientist to refuse to provide his data for independent examination when asked, but Targ and Puthoff consistently refused to allow Marks and Kammann to see copies of the transcripts. Marks and Kammann were, however, able to obtain copies of the transcripts from the judge who used them. The transcripts were found to contain a wealth of cues.^[19]

Marks noted that when the cues were eliminated the results fell to a chance level.^[20] James Randi noted that controlled tests by several other researchers, eliminating several sources of cuing and extraneous evidence present in the original tests, produced negative results. Students were also able to solve Puthoff and Targ's locations from the clues that had inadvertently been included in the transcripts.^[21] Marks and Kamman concluded: "Until remote viewing can be confirmed in conditions which prevent sensory cueing the conclusions of Targ and Puthoff remain an unsubstantiated hypothesis."^[22] According to Martin Gardner, Puthoff (and Targ) "imagined they could do research in parapsychology but instead dealt with 'psychics' who were cleverer than they were".^[23]

In the late 1980s and 1990s, Puthoff co-authored papers^[24][25] using the model of stochastic electrodynamics that leads to a model of inertia as an electromagnetic drag force on accelerating particles, produced by interaction with the zero-point field.^[26] This concept built on Andrei Sakharov's proposal in 1968 that the gravitational constant was a consequence of zero-point fluctuations in the vacuum.^[27]: 162 One of his 1989 papers was disputed by S. Carlip for containing a serious computational error which makes the effect negligible;^[28] Puthoff responded that a different parameter value in the model would restore its usefulness.^[27] The 1994 paper was the subject of a news article in Science.^[29] Subsequent analysis by Yefim S. Levin raising numerous questions concerning the mathematical correctness of the formula and the use of non-relativistic treatments of magnetic effects, concluding that model does not show inertia as a result of zero-point-field effects.^[30] The cosmological implications of a different 1989 paper by Puthoff^[31] on the origin electromagnetic zero point energy was examined by Paul S. Wesson^[32] Among numerous difficulties, general relativity requires that such energy not gravitate, so it cannot be similar to electromagnetic radiation.

Building on earlier theoretical work by Robert L. Forward leveraging the Casimir force to extract electrical energy,^[33] Daniel Cole and Puthoff analyzed the thermodynamics of a simple hypothetical Casimir force device.^[34] The hypothetical devices discussed in these articles are capacitors, multiple layers of charged conductors sufficiently close for the short range Casimir force to compress the structure. This work against the mutual repulsion of the conductors stores electrical energy; external electricity would be needed to recharge the device. Mechanical and thermal devices based on Casimir forces have been studied by other authors.^[35]

Massimo Pigliucci called Puthoff's hopes to extract zero-point energy as running contrary to the laws of physics: "a proposition... that violates basic principles of thermodynamics and that is considered pseudoscience by credentialed physicists."^[36]

• Henry Gordon (1988). Extrasensory Deception: ESP, Psychics, Shirley MacLaine, Ghosts, UFOs. Macmillan of Canada. ISBN 0-7715-9539-5
• James Randi (1982). Flim-Flam! Psychics, ESP, Unicorns, and Other Delusions. New York: Prometheus Books. pp. 131–160. ISBN 0-87975-198-3.

• Harold E. Puthoff at IMDb
• Profile at Earthtech International