Jonathan Caplan KC

Career as Barrister

Jonathan Caplan is a King's Counsel (KC)—the highest rank in the UK legal profession—and one of Britain's premier barristers. His career spent evaluating evidence in complex cases has provided him with a professional discipline rare in UFO research: the ability to assess testimony, documentation, and witness credibility by the standards of courtroom evidence. His legal reputation and standing have, by his account, "opened doors that were closed to other researchers," giving him access to classified witnesses and sources who might not speak to amateur investigators.

Five Decades of UFO Investigation

Caplan has dedicated over fifty years to systematically gathering evidence on unidentified aerial phenomena. For many years, he served on the editorial board of a leading international UFO journal, where he worked with distinguished correspondents to vet and validate incoming reports. His approach has always been methodical: working through networks of military insiders, intelligence officers, scientists, and politicians across multiple countries to assemble primary-source testimony rather than recycled claims.

His dual roles—as a practising barrister and as an archive custodian of UAP evidence—have made him a rare figure in ufology: someone with both professional credibility in law and sustained, disciplined investigation of a fringe subject.

"Not For Disclosure" (2026)

In June 2026, Caplan published "Not For Disclosure: The Truth about UFOs, the World's Best Kept Secret" through Century, an imprint of Penguin Random House. The book became a Sunday Times Bestseller and has been described as "the most serious and sourced book ever published on the subject of UAPs."

The work consolidates five decades of correspondence, interviews, and documentation. Caplan frames UAP evidence in legal terms: sworn statements, corroborating testimony, documentary chains of custody, and the credibility assessment of sources. His argument is that the evidence for extraterrestrial visitation and crash retrievals, when examined by evidentiary standards, is robust enough to warrant serious institutional investigation. In media discussions around the book, Caplan has stated that "aliens have landed on Earth—and some of the many distinct species have been captured."

Evidence-Based Methodology

Caplan's approach distinguishes him from sensationalist UFO commentators. Rather than promoting anecdotes or speculation, he builds a case—in the legal sense—by cross-referencing witnesses, checking their credentials, testing their consistency against declassified documents, and identifying corroboration. His background in cross-examination and evidence law means he is trained to spot inconsistencies, bias, and unreliability in ways that intuitive researchers often miss.

He has interviewed scientists, military pilots, intelligence officials, and politicians who have firsthand knowledge of UAP incidents or recovery operations. Many of these sources remain unnamed in his publications for security or privacy reasons, a constraint that distinguishes "Not For Disclosure" from gossip-based UFO literature: Caplan respects confidentiality agreements and source protection, a legal instinct rather than a ufological one.