Double Deuce and A Catskill Eagle by Robert B. Parker. But I liked the books, Double Deuce more than Eagle. Parker's style is simple and often stark. Yet now and again the reader encounters a lyric, nearly poetic paragraph. Underlying the tough-guy realism is a subtle and gentle parody of the genre.
Intelligence is at work here.
By the way, Spenser has a home page. The Hot Zone by Richard Preston. This piece of non-fiction is not for the squeamish. Preston is a prominent science writer, and this book is the true story of the emergence of the Ebola virus. It's graphic and scary and very well told.