Graham Hancock (born 2 August 1950) is a British writer and journalist. Hancock specialises in unconventional theories involving ancient civilizations, stone monuments or megaliths, altered states of consciousness, ancient myths and astronomical/astrological data from the past. One of the main themes running through many of his books is a posited global connection with a "mother culture" from which he believes all ancient historical civilizations sprang.

Hancock's breakthrough to bestseller status came in 1992 with the publication of The Sign and The Seal, his epic investigation into the mystique and whereabouts today of the lost Ark of the Covenant. 'Hancock has invented a new genre,' commented The Guardian, 'an intellectual whodunit by a do-it-yourself sleuth.' Fingerprints of the Gods, published in 1995 confirmed Hancock's growing reputation. Described as 'one of the intellectual landmarks of the decade' by the Literary Review, this book has now sold more than three million copies and continues to be in demand all around the world. Subsequent works such as Keeper Of Genesis (The Message of the Sphinx in the US) with co-author Robert Bauval, and Heaven's Mirror, with photographer Santha Faiia, have also been Number 1 bestsellers, the latter accompanied by Hancock's three-part television series Quest For the Lost Civilisation.

In 2002 Hancock published Underworld: Flooded Kingdoms of the Ice Age to great critical acclaim, and hosted the accompanying major TV series. This was the culmination of years of research and on-hand dives at ancient underwater ruins. Arguing that many of the clues to the origin of civilization lay underwater, on coastal regions once above water but flooded at the end of the last Ice age, Underworld offered tangible archaeological evidence that myths and legends of ancient floods were not to be dismissed out of hand.

Graham's next venture Talisman: Sacred Cities, Secret Faith, co-authored by Robert Bauval, was published in 2004. This work, a decade in preparation, returns to the themes last dealt with in Keeper Of Genesis, seeking further evidence for the continuation of a secret astronomical cult into modern times. It is a roller-coaster intellectual journey through the back streets and rat runs of history to uncover the traces in architecture and monuments of a secret religion that has shaped the world.

In 2005 Graham published Supernatural: Meetings with The Ancient Teachers of Mankind, an investigation of shamanism and the origins of religion. This controversial book suggests that experiences in altered states of consciousness have played a fundamental role in the evolution of human culture, and that other realities - indeed parallel worlds - surround us all the time but are not normally accessible to our senses.

While researching Supernatural Hancock travelled to the Amazon to drink visionary brew Ayahuasca - the Vine of Souls - used by shamans for more than 4000 years. It was his experiences with the vine lead to his latest work, Entangled. Written with the same page-turning appeal that has made his non-fiction so popular Entangled is his first novel. It tells the story of a supernatural battle of good against evil fought out across the dimension of time on the human plane.