Danielle and Dominique-Pierre Guéret weren’t just bored when they decided to embark on a seven-year quest to meticulously document the architecture and painted murals of the Kingdom’s thousands of pagodas; they were set on calling attention to what they saw as one of Cambodia’s most precious but ignored cultural treasures.

The result of their endeavour is The Khmer Pagoda, a condensed “best-of” anthology of their research into the country’s pagodas built before 1975, which will be available in select bookstores beginning this weekend.

The Guérets’ relationship with the country dates back to the United Nations Transitional Authority of Cambodia years, when the former French serviceman Dominique-Pierre, 71, was first stationed in Cambodia. Danielle, 70, an archaeologist who trained and taught at the prestigious École du Louvre, took up a teaching position at the Royal University of Fine Arts.

“We wanted something to do on the weekends outside of work, and it’s not like we could go every Sunday to the swimming pool of the [Raffles Hotel Le] Royal,” Dominique-Pierre said at the couple’s Phnom Penh hotel this week.

So they began visiting all the Angkorian and pre-Angkorian temples they could, and from these trips they soon had enough for a book, the encyclopaedic 300-page collection Cambodge, published in 2009.

The idea to document pagodas came to them after reading a 2004 publication by the International Institute for Advanced Asian Studies (CESMEO) in Turin, through which it became clear that little formal research had been done on paintings in Cambodian pagodas, with even the fate of important murals largely unknown.

“In fact, nobody knew about these . . . It was about old paintings, but nobody knew what had become of them,” Dominique-Pierre said. So starting in Phnom Penh in 2004 they visited first one, then two, then another and found that many viharas, or the main sanctuary of a pagoda, were decorated with paintings that survived years of Khmer Rouge rule, war and neglect.

“We were inspired and intrigued by these murals, and that’s how it started,” Danielle said. “As I am a professor of archaeology, old stones interest me – I found [with these paintings] another cultural heritage that nobody knew about and not one person was interested in.”

In the years spent on the project they saw practically no Western or Asian tourists as they measured, documented and indexed nearly 3,400 pagodas.

“In 2005, on weekends we did a repertoire of 800 pagodas in all the provinces,” Dominique-Pierre said.

The pair then returned to France but dedicated one month each year to continuing their work until 2010 when they settled back in the Kingdom, ultimately completing their survey in August 2011.

At just 179 pages, The Khmer Pagoda is just a small fraction of the inventory they created, which is the first – as far as they know – since 1916.

“We found no other listings thereafter – not at the national archives or any others,” Danielle said.

The book focuses on the pagodas they deemed most interesting and noteworthy, both architecturally and for their paintings, and most historically significant. Divided into 13 geographical sectors, readers are presented a handy guide to the country’s religious structures, which are especially concentrated around the Tonle Sap and in the southern provinces.

“The general idea is for people to discover this religious and cultural heritage . . . without too much commentary,” Dominique-Pierre notes.

The full catalogue of the pagodas – which consisted of going through reams of archives, snapping some 120,000 photographs – was published in two three-part theses submitted to Paris’s La Sorbonne university.

“We can never say we saw all of them, but nonetheless, we mentioned in the theses five or six that may have been old that we did not see because the road was impassable,” Dominique remarked.

It was an undertaking with some close calls, including when their car fell into the river when a bridge collapsed.

The book comprehensively describes the architecture and layout of Cambodia’s pagoda complexes between the late 19th century and 1975, with a glossary of terms for different features and characteristics. Dominique-Pierre took the lead on this aspect of their research, and found that during certain time periods there were set “types” of architecture.

But what neither the archives, nor any other source, could explain were the painted murals, which typically depict scenes from the Jataka tales of the birth and life of the Buddha, the Reamker – the Khmer version of the Ramayana – and occasionally the lives of royalty.

Danielle, who had the academic background to “read paintings”, took it on herself to make sense of it all. She credits the scholar Jean Boisselier, who wrote Thai Painting, for providing her some direction. Using the rare examples of viharas in which the date of construction and murals were clear, she would identify a style which could then be used to date other paintings elsewhere.

“I studied the way characters were represented, so two-dimensional characters would place us in the oldest time period . . . as we see more dimensions, and more motions, it moves the paintings forward in time,” she said.

But perhaps most intriguing were the clear imprints and signatures of the society and culture in which the painter lived. One such example can be found in Phnom Penh’s Wat Teuk Thla, where a mural depicts the three daughters of Mara trying to tempt or distract the Buddha. Rather than traditional outfits, they don clothing that is both Western and Eastern and are striking European ballet poses.

Danielle discovered that there had been a French finishing school nearby where young girls from the Khmer upper class learned – among other things – European ballet.

“You’ll see things that you’d never have thought to see a Khmer woman wear [at the time]: a slip dress, a French-style bathing suit . . . So these are Cambodian painters, in the cities, that are reproducing what they themselves saw,” she said, noting that most often this imaginative expression in murals of the daughters of Mara, the temptress demon. “[This is] perhaps to criticise Westerners,” she said.

A range of elements – like weaponry, shoe design and the appearance of airplanes or a Vespa – helped place the paintings in time.

Sadly, the Guérets’ note, even when designated national heritage sites by the Ministry of Culture these pagodas and the paintings within are hardly preserved. The murals are often painted over during “restoration work” or the walls are even knocked down, as was the case at Wat Kampong Thom earlier this year, where a cherished monastic temple was demolished in September to make way for new construction.

With their book, the Guérets said, they hope to create public awareness for the need for stronger preservation. “It’s a completely unappreciated heritage,” Danielle said.

The Khmer Pagoda, or “La Pagode Khmere” (KAM éditions, 179pp, $25) will be available in English at Monument Books, with a launch at the Norodom location on Saturday, and in French at Carnets d’Asie with a launch on Friday.

Open Wine restaurant will also host a reservations-only dinner tonight, in the company of the Guérets, with a copy of the book included with the price of the meal.