My opinion: Ross Macdonald wrote the very best private investigator novels, and among the overall finest mysteries, ever written. I believe that The Galton Case, The Chill, and The Far Side of the Dollar reflect his skill at the pinnacle of his career. I rate all of his Lew Archer novels at four and a half or five stars. His non-Archer books such as Moving Target (made into a movie with Paul Newman) rate four stars or higher.
Many mystery readers consider Ross Macdonald's Lew Archer books to be the best series of American private detective fiction ever written. He took the path laid by Hammett and Chandler and upped the ante on plot and social relevance. This story of a con game that moves from the mansions of wealthy Californians to the rooming houses of down and out Canadian grifters is eloquent and surprising.