All of the Lew Archer mysteries by Ross Macdonald are very good, and all but two or three are excellent. This one is in the top three of four, which means it is one of the best mystery novels ever written, and beyond that, it is an excellent novel, period.
It is well plotted, tight, and plausible. (I didn't say probable.) I do not agree with some other reviewers here who think that certain aspects are very unlikely. To say more would be a spoiler, and THAT would be near criminal.
The characterizations are excellent. It flows smoothly, a real page turner, hard to put down. It is quite complex, and the reader would be rewarded by keeping a note pad and jotting down the first time and place a character is mentioned, and other key points. (I always intend to do so, but usually can't keep it up for long.) But beyond the mystery story aspects, no other mystery novelist that I am aware of has so many insightful observations, compelling similes, and such deep observations on the human condition.
I have read all of the Lew Archer novels at least twice over a period of twenty five years. This is perhaps my personal favorite, even though it may not be the absolute best, if there is such a thing. Others in my list of favorites and bests are Sleeping Beauty and The Zebra-Striped Hearse. It doesn't get any better than this folks.