I confess I haven't actually read this series. My tastes in mystery fiction run more toward the classic drawing-room stuff.

I do however remember the 'colour-scheme' titles with great fondness. The Lonely Silver Rain...how seriously cool can a mystery novel get?

I have read all the Trav McGee series, and I think they are great. The color-title scheme is funny, but to create a detective with an insight, who has a lot of women but thinks love is important, who takes time to think and who has a hairy economist as friend makes this very special. I don't care very much for standard detective/crime novels: somebody gets killed, somebody finds out. But a detective like mcgee is so special its interesting to read about him.

I must say that some of the other books by the same author did not strike me as special. The characters weren't that interesting for me.

Still, I am very sad that John D. Macdonald died after such a short time writing and that there will be no more McGee novels.

I agree, convincingly eccentric detectives are very few and far between. (As opposed to mere collections of quirks, a la Hercule Poirot.)
The Nero Wolfe series is my favourite for much the same reason.

I've found MacDonald's non-McGee stories uneven in quality too. I liked "The Girl, the Gold Watch and Everything", Condominium and a few other stories but, there were several I tried and didn't care for.

A question about the McGee novels: some of the early novels give his boats name - in the translated version - as "Spade 7", but later it's called "The Busted Flush". Is the early version a translation error, or was there some retroconning? (Reading the very early novels, McGee doesn't seem to be that fleshed out compared to the latter works.)

In "Pale gray of guilt", we meet the woman Puss Kilian, who leaves McGee on New Year, writing him a letter.

In "The lonely silver rain", when McGees daughter by Puss turns up, McGee shows her the letter, and it has changed remarkably.

A pity that there were no more McGee stories after that - his daughter seemed to be quite adept at the trade for a kid, after all, sneaking around to place the cats undetected! He could have teamed up with her. (Then again, whenever he had a lady with him during the adventures, he had back luck, and most often lost the lady during the adventure. Maybe he doesn't want to loose his daughter, too?)

A much belated response to Constanze.

McGee's boat was always called The Busted Flush in the novels. The Spade 7 thing must have been a translation goof.