They are some of the greatest treasures of Tibetan Buddhist culture: ancient murals showing the life of the Buddha and the secrets of meditation. Many are hidden in remote monasteries or temples whose walls are crumbling, but a remarkable project has recorded the paintings before they disappear for ever.

The American photographer and writer Thomas Laird spent a decade living among yak herders, farmers and monks while travelling across the Tibetan plateau in search of masterpieces that few have been able to see, let alone photograph.

The result is 998 copies of Murals of Tibet, an enormous – more than 2ft-long – publication. All copies have been signed and blessed by the Dalai Lama, whose first lessons in Buddhism came from some of the murals before he could even read.

Many of the paintings have become visible for the first time through Laird’s work. Some were created in windowless areas so high up that only fragments of the vast paintings have been glimpsed with torches and binoculars.

Facebook Twitter Pinterest Lord and Lady of the Cemetery (late 19th–early 20th century) in Nechung Chapel. Photograph: Thomas Laird

Determined to convey the paintings’ spiritual and emotional significance, Laird developed a photographic “stitch system” that allowed 300 murals to be reproduced in extraordinary detail.

“There’s a huge chapter of the world’s heritage that’s unknown and undocumented,” said Laird. “I was terrified that 1,000 years of these murals was going to be lost for future generations. There’s a thousand years of Tibetan murals that have been very difficult to see. If you go to Tibet, you can’t see the murals. Very often there’s a giant pillar in front of them or the murals begin 10ft in the air. And when you’re standing beneath them, you’re looking at a distorted view in darkness. But imagine seeing the great murals of Europe for the first time. That’s what we’ve done. It’s an amazing moment – a technological breakthrough.”

His technique involved capturing hundreds of images of a mural which are blended together. “These are not photographs. I create new images that are faithful to what’s there, but when you go there you can’t see it. I’m making the invisible visible. Now, for the first time, you can read every single mural. You can see fingerprints from the original artists.”

The lost murals include a 15th-century example at the Gongkar Choede monastery – an “enlightenment scene” depicting Buddha surrounded by a rainbow aura. Laird said: “I can show you images of it on the wall and then as a pile of rubble on the floor. It was painted by the greatest artist of the 15th century, Khyentse Chenmo. His hand was like Leonardo’s, conveying the most subtle nuances.” Water had seeped into the wall over the centuries until the plaster finally separated and the wall collapsed. Part of the Buddha’s face can now be seen in a fragment lying on the floor.

“There are thousands of square metres of murals scattered across the Tibetan plateau of varying age, and it’s practically impossible to conserve them all,” he added.He writes in his book that “the murals were a layer in the Dalai Lama’s education, before he learned to read” and that Tibetans use a particular phrase about the greatest murals as having the power to generate, for the pilgrim, “thongdrol”, meaning “liberation through seeing”.

Laird, a Buddhist convert, lived in Nepal for 35 years, working as a photojournalist for publications such as Time. His non-fiction books include a history of Tibet in which, over two years in the 1990s, he conducted 50 hours of interviews with the Dalai Lama, who nicknamed him “troublemaker”.

Discussing the new Murals of Tibet publication, he said: “He’s never signed a 1,000 copies of a book before. That was an amazing moment.”

The 1,200-page, two-volume study, with essays by international scholars on the murals’ philosophical and religious history and teachings, will be published this month by Taschen.