Ivan Doig, author of 16 books including This House of Sky and The Whistling Season, died of multiple myeloma on the morning of April 9 at his home in Seattle. He was 75.

Doig was born in 1939 and grew up in Montana. Before he was drawn to writing books, he worked as a ranch hand, and earned multiple degrees: bachelor’s and master’s degrees in journalism from Northwestern University, and a Ph.D. in history from the University of Washington. He wrote of his upbringing in his memoir This House of Sky, which as a finalist for the National Book Award. The majority of his novels were set in the imagined region of Two Medicine County, and three of them featured his McCaskill characters.

“Ivan Doig has been, from This House of Sky, his first grand entry into literature, one of the great American voices,” said writer Thomas Keneally. “Full of grace, abounding in humanity, easeful in narration, hypnotic in pace, grand in range.”

“Ivan was one of the greats,” says Riverhead publisher Geoff Kloske, in a statement. “We have lost a friend, a beloved author, and a national treasure.”

Doig’s final work, Last Bus to Wisdom, will be published Aug. 18.