NEW YORK (Reuters) - Dutch painter Vincent van Gogh had a simple philosophy for producing good work -- “you have to eat well, be well housed, have a screw from time to time, smoke your pipe and drink your coffee in peace.”

That advice to French artist and poet Emile Bernard in 1888 is from one of 20 letters the painter wrote to his younger counterpart between 1887 and 1889 and displayed at New York’s Morgan Library and Museum starting on Friday.

“Art is long and life is short, and we must wait patiently while trying to sell our skin dearly,” wrote van Gogh, whose paintings now sell for tens of millions of dollars.

His “Portrait of Dr. Gachet” sold in 1990 for $82.5 million, making it one of the most expensive pieces of art to be auctioned.

The letters were written in French and an English translation was provided by the museum.

Famed for his powerful use of color and coarse brushwork, Van Gogh also writes about his health problems after he was committed to an asylum in Saint-Remy, France, suffering from mental illness. He eventually committed suicide in 1890.

“If I haven’t written for a long time, it’s because, having to struggle against my illness and to calm my head, I hardly felt like having discussions, and found danger in these abstractions,” he wrote in November 1889.

“Here’s a description of a canvas that I have in front of me at the moment. A view of the garden of the asylum where I am, in the right a gray terrace, a section of house, some rosebushes that have lost their flowers; on the left, the earth of the garden -- red ocher -- earth burnt by the sun, covered in fallen pine twigs,” he wrote.

Most of his letters were signed “Ever yours, Vincent.”

Jennifer Tonkovich, curator of The Morgan Library and Museum’s drawings and paintings, said the exhibit marked the first time in nearly 70 years that the letters would be seen publicly. They are the largest collection of letters by the painter outside the van Gogh Museum in Amsterdam.

“They are among the most frank, honest and exciting and open letters that van Gogh ever wrote because they were written during the height of his creativity to another artist who was much younger so in no way intimidating,” she said.

She said collectors Eugene and Clare Thaw own 19 of the letters, but have made them a promised gift to the Morgan.

“The letters tell us so much about him, everything from what it was like to physically be him, his problems with health and diet, his philosophies about sexual activity and his religious beliefs,” Tonkovich said.

The letters will be on display until January.