Caleb Carr discusses grief and dying — subjects that linger over his new nonfiction book, “My Beloved Monster,” and now loom over what might be the final months of his life.

Caleb Carr, a military historian and author whose experience of childhood abuse drove him to explore the roots of violence — most famously in his 1994 best seller, “The Alienist,” a period ...

Carr, 68, has cancer, which started in his prostate and has spread throughout his body. “If I could be around when the book is published, that would be really nice,” he said in late January.