Early Autumn; Death is a Dirty Trick; Count on the Saint

The Detective Book Club produced volumes of three crime novels from 1942 to 1999. Originally monthly, near the end they dwindled down to just a few per year. Many famous detective and crime novelists had their early works featured in DBC editions. Often, books were published in DBC editions before, or at the same time as they were published in mass market form.
About the authors:
Robert B. Parker: Parker has had a significant impact on television, having created detectives Spenser (played by Robert Urich) and Jesse Stone (played by Tom Selleck). Parker also created two other detective series, and as a tribute to their quality, all four series have been continued by other authors since Parker's death in 2010. All together, Parker published over 70 books. Early Autumn is the seventh Spenser novel.
Judson Philips Judson Philips, a man of many detectives. Under his own name and the pen name Hugh Pentecost, Philips published over 100 books, most of which were in one of eight different series. The largest series featured Pierre Chambrun with 22 books. In spite of all these series, almost a quarter of his books were stand-alone novels. Death is a Dirty Trick is the sixteenth Peter Styles novel.
Leslie Charteris: Charteris is well known as the creator of his character Simon Templar, also known as The Saint. Charteris published over 60 books about the Saint, which lead to two television series and a movie or two. Count on the Saint is something like the 53rd Saint novel.