What are some books in the Spenser series by Robert B. Parker?

Books in Robert B. Parker's Spenser series include "Sixkill," "The Professional," "Painted Ladies," "Rough Weather" and "Cold Service." After Parker's death in 2010, his family and publisher selected novelist Ace Atkins to continue the Spenser series.

Parker began writing his first novel in 1971. By 1979, he had published five Spenser novels and began devoting himself to writing full time. Spenser is a private detective whose first name is never revealed to the reader. A former state trooper in Suffolk County, Massachusetts, Spenser operates primarily within the city of Boston. Critics have praised the Spenser series for its multicultural cast of characters.