Crime writer Elmore Leonard suffered a stroke a week ago and remains hospitalized at an undisclosed Detroit area hospital, his longtime researcher Gregg Sutter confirmed to Susan Whitall of The Detroit News today.

“Elmore had a stroke; it happened a week ago, last Monday,” Sutter told Whitall. “He’s doing better every day, and the family is guardedly optimistic. He’s showing great spirit. He’s a fighter, and we’re glad to see that.”

With 45 novels under his belt, if Leonard, 87, had slowed down his writing schedule prior to the stroke, it’s only compared to his prolific earlier days. He’s been working on his latest book.

“He’s very much into his 46th novel,” Sutter said, “working very hard.”

Read more: Detroit News