Henrik Drescher is standing in front of a class of illustration students at the Maine College of Art, in Portland, in the United States. It's 9am and the Dane - one of the most revered illustrators in the world - wastes no time in offering what may be the best advice the students will ever hear.

"I want you to cultivate the muse," he barks at them. "You're on a dead-line but you need to loosen up. You need to learn how to counteract the anti-muse. All of you are talented but some of you will not be able to let go of the anti-muse, perhaps for your entire lives. Focus on the muse. If you do something interesting to you, it will shine."

Drescher and his artist wife, Wu Wing-yee, have landed in Maine as part of their US tour teaching at art colleges and publicising Drescher's new book, China Days: A Visual Journal From China's Wild West.

A regular illustrator for The New York Times, The Washington Post, Time and Rolling Stone, and until last year a weekly contributor to Post Magazine - his books are also housed in the collections of New York's Museum of Modern Art and London's Victoria and Albert Museum - Drescher is venerated in illustration circles.

His children's books, known for their imaginative power, have topped The New York Times' Best Illustrated Children's Books of the Year list four times. His artistic books attract a cult-like following. In Turbulence: A Log Book he mixes Hindu creation myths with the mind-warping narrative of a traveller on a steamship sailing into "an ocean of bliss". China Days is the artistic embodiment of the 11 years Drescher and Wu have spent living in the country.

"We met in Hong Kong," says Wu, over coffee in the college's downstairs cafeteria, once the students have been inspired, and terrified, into action.

"Wing grew up in a little house in Tai Hang, a little shopfront," her husband explains. "Her family was very traditional; her father was a driver and her mother a housewife. They played mahjong everyday."

Wu was a highly driven student who, by the age of 17, was studying graphic design at Polytechnic University. After graduating, she enrolled at the Guangzhou Academy of Fine Arts and studied oil painting.

She remembers bringing up the move to Guangzhou to her conservative family, who strongly discouraged her pursuit of the arts.

"We were at home having dinner and I told them my plans. My two brothers put down their chopsticks and said, 'No'. But I'd already paid the tuition fees."

After she graduated, she headed to the California College of the Arts to study illustration and ceramics. In 1990, she returned to Hong Kong to teach at the Museum of Art and the Art School. "I was one of the few people bringing back the American perspective to Hong Kong, [things such as] ceramics with a sculptural edge," she reminisces. "I was trained in the West Coast Bay, where everything was possible."

In 1993, Wu was awarded the Sir Edward Youde Memorial Fellowship for Overseas Studies - the first time the prize was given to someone in the visual arts in Hong Kong. It funded her master's in arts administration at New York's Columbia University. Her dissertation described the setting up of a children's museum in Hong Kong.

The museum never materialised but, when she returned to the city, Wu's dissertation informed a policy brief for exhibits at the Children's Discovery Gallery of the recently established Heritage Museum.

Wu threw herself into her work, collaborating with the Museum of Art and setting up the Ceramic Archive, which logs the development of ceramic art since the 1960s. She taught ceramics all over the city, established the Dragon Wing Workshop in Tin Hau (which operated for five years), and did occasional illustrations for Time magazine.

In 2000, she attended a Time dinner in Hong Kong and met the man who would become her partner in art and romance.

Drescher was born in Copenhagen, Denmark, and emigrated to the United States with his family in 1967, aged 12. He was a student at Boston's School of the Museum of Fine Arts but quit after one semester to begin a nomadic life and blaze a singular path in illustration. He worked in Mexico, the United States, Europe and New Zealand.

Drescher and Wu's meeting over dinner came at the perfect moment. Wu says she was about to "implode" from exhaustion. Having been recently admitted to hospital with pneumonia, she knew she was burned out.

"I thought, 'I need to retire now'," she says, laughing. "My work was stuck, it was not developing. I called my sister and asked her to take over the workshop. I gave her the keys and just walked out."

Wu disappeared from the Hong Kong art scene.

Romance ensued, and she and Drescher moved to Guangzhou, where the cost of living was far lower than in Hong Kong. Being artists and illustrators, they could live anywhere they had an internet connection.

Then, as Drescher writes in China Days, "One scorching spring afternoon in 2002, [the couple] boarded a sleeper train from Guangzhou's chaotic central station for a 27-hour journey to Yunnan province. Our idea was to take a one-month escape from the fetid heat of Guangzhou … to the high arid mountains of southwestern China. The next morning, looking out the windows of our rumbling train, I saw for the first time the mountains of Guizhou: they jutted up like huge anthills between flowering rapeseed fields.

"In my mind, these impossible mountains existed only as artistic inventions on ancient scrolls. This proved to be the beginning of a long series of eye-opening, mind-popping experiences in my new China life."

Smitten, the couple moved to Dali.

"As an artist, I've tried to make it a priority to live in places that offer me two most valuable resources for creativity: time and space," writes Drescher. "In Dali, Wing and I found both. The clean, dry air and sun-filled days lulled us into a hypnotic rhythm of work and play unequalled anywhere we'd lived before."

They stayed in hotels and guesthouses, usually renting two rooms: one to live in, the other to work in. Then they moved into a rented courtyard house and, for a while, even lived in a storefront. By 2005, they had bought and renovated a small, two-storey townhouse.

Their tourist town in the fertile valleys and mountains of Yunnan is depicted in China Days in a series of sketches, collages and photographs of places and personalities; elderly men with birdcages; the Bai people's annual "flirting festival"; and observations of pollution and how it is linked to America's appetite for cheap goods.

"Visiting barbershops is a great way to get a feel for a place," writes Drescher. "My favourite shop in Dali is Mr Yang's on Renmin Lu. His sign advertises 'Electric Permanents'. (Yes, electric!) When he's not cutting hair, Mr Yang teaches the erhu (a Chinese fiddle). On the wall hangs a portrait of Mr Yang giving himself a pompadour (pre-Photoshop magic). Unfortunately, the old man is retiring, leaving the business to his ham-fisted son."

This description is accompanied by sketches of the shop and a series of photos of Dali residents, onto which surrealistic, outrageous pompadour hairstyles have been drawn.

Drescher also depicts the old town of Dali, which "is disappearing fast".

"Even the 'ancient' city wall is new; it was rebuilt in the late 1990s. But to tourists, this is of no concern as long as there's a photo op when they step off the bus," he writes. "Dali attracts a motley crowd of starry-eyed hippie kids, spoiled celebrities, nouveau riche leather-clad Buddha freaks, wannabe poets and artists and other gangsters, hucksters, and snake oil salesmen, lending the place an almost Wild West quality."

Another section of his book is devoted to images of Mao.

Drescher writes, "To most young Chinese, Mao Tse-tung is irrelevant, a kind of Chinese George Washington, distant and symbolic. I asked a cab driver why so many people still had images of the man in their homes. He explained that, while alive, Mao killed so many people that, in death, he lived on as an ultra-bad-ass god to scare off lesser bad-ass gods. He said that some people keep images of the chairman in their kitchens to chase away rats and cockroaches."

Drescher sees the mainland through Western eyes, of course, but he manages to delve far further beneath the surface than any tourist could hope to. In one double-page spread he writes about families who send their children overseas for education: "These people are called ' tai kong ren' - astronauts - because they're exploring 'outer space'."

Drescher's unique shan shui (mountain-water) landscapes open each chapter. They were painted on large canvases before being scanned and scaled down for the book. His hallmark pen and ink, collage and painting style describes mountainscapes wherein the greenery is interwoven with futuristic pipes and boiling machines.

"I have no idea exactly why I'm drawn to shan shui pictures," he says. "Maybe because they are so metaphorical? I'm attracted to the idea that what you see isn't necessarily what you think you see."

China Days marks the first time Drescher has recorded real places and times in a book.

"I never do that. I never paint about the place I'm in," he muses. "Most of my stuff comes from here." He points to his head.

"It's the kind of book you can do over many years," he adds. "The drawings are from when I first arrived [in China]. The observations I've boiled down over the past two years. It's a process of boiling and stewing; it's a very personal book. It's a time capsule."

Drescher and Wu have produced dozens of publications between them and they clearly see the book as an important record of artistic practice. But isn't the printed page under threat in these increasingly virtual times?

"That stuff's useless," says Drescher, of the internet. "That's just information. Even the images; you can't feel anything with depth with that stuff. You can't fall in love with a jpeg. I do have stuff online but it is just a distant reflection. It's the CliffsNotes.

"Since the [2008 global economic] crash, people like me have had a harder time publishing. The [children's books] market really contracted so [publishers] only wanted things that are sweet. That's what happens. If there's money around, then you can explore. If there's not, you have to stick with the sure sellers."

Nevertheless, the couple has continued to host a seemingly endless list of workshops, exhibitions and artist residencies around the world.

While Drescher is the electric mind - conceptual and analytical - Wu is the enormous heart. She speaks softly and produces elemental creations - from installations to print-made works and sound-based pieces - that explore concepts of time, memory, fire, energy and the human body. Many projects, she says, take between five and 10 years to complete.

One of Wu's best remembered projects was her Cages series - an investigation into positive and negative space. She displayed 108 kitsch objects she'd picked up in Chinatowns around the world - ceramic rice spoons and Guanyin statues, "objects you can't find in China anymore" - in ceramic cages, which she had fired with the found pieces already inside. The collection was displayed in the Guangdong Museum of Art in 2004.

Despite their love of Dali - and the downtown studio they share with their blind dog, Tofu - the time is coming for the couple to pack up and leave. The couple are spending more time in the US - they both now have green cards - although they can still be spotted from time to time in Tai Hang.

There's a certain irony to Drescher conducting workshops in art schools, given that he dropped out of his own studies so early. Since then, he has learned how to bypass the inner critic. He has an intimate relationship with the muse - the furthest reaches of the human imagination, the place where the magic lies - and he is fearless about communing with it.

"I'm self-taught," he admits. "I work within the limitations of my ability. My weakness is my strength."