I'm now reading one of his earliest, A Fox Inside. I hadn't even known it existed. It was first published in 1955 in Britain; Stacton was 32 then, but already writing confidently in his own voice. And it's extraordinary.
A Fox Inside is a kind of noir novel about a death in a family of Very Old California Money, specifically on March 15, 1953, in Bolinas, north of San Francisco. Stacton's world seems very contemporary despite the lack of cell phones and websites. (Much of the action takes place on the Stanford campus and the San Jose area, long before they became Silicon Valley.)
Stacton moves his point of view from one character to another, and after starting his novel with the death, he moves gracefully through extended flashbacks to the early 1940s and before, showing how the characters got into their situation. His social perceptiveness foreshadows his historical novels; this thriller is itself now historical, a remarkable evocation of a lost era. His protagonist, Luke, is an outsider despised by the wealthy Barnes matriarch, yet drawn into trying to save her and her daughter from their own folly.
His later work was both praised and damned for its reliance on aphorisms; they certainly turn up here, but I can believe that Luke, the successful outsider, is still alienated enough to observe the world with Stacton's detached irony.
And while the historical novels are notably short on extended dialogue, Stacton here is a master of talk you can hear—better said, overhear. His main characters are very much people born in the 1920s or earlier, thinking and speaking in sentences without sounding artificial.
I haven't finished A Fox Inside, but Stacton clearly knows what he's doing and I'm not afraid of a disappointing ending. This is what Raymond Chandler could have done, if he'd ever grown up.