Lots of writers have written under pseudonyms, particularly when working in new genres (Robert Galbraith) or trying something new in the same one (Richard Bachman, Richard Stark). And pretty much
everyone wrote smutty books under pseudonyms, for the twenty or so years that "smutty books" were a genre in North America -- who would want their own names on
that crap?
But, then, who would think people would be still reading "that crap" forty years later, and trying to find all of the books by a particular author or pseudonym?
So the writers that did write smutty books, if they were still around a few decades later, still writing whatever else they turned to writing, and not completely turned to hatred of their old smut, tended to bring it all back, under their own names, because at least some of their fans were interested in those books. (Whether the interest was due to the author, due to it being smut, due to the age, due to the particular kind of smut, or some combination thereof was much more individual.)
Most of them were not precious about that republication. This is stuff they wrote quickly, generally when quite young, for a very specific market. But some pseudonyms feel more "real" to their authors than others. And so when Lawrence Block came to bring back his old smutty books -- and he had a lot of them, close to fifty under names like Sheldon Lord, Jill Emerson, and Andrew Shaw -- most of them were just republished as by Block.
But the books originally credited to Jill Emerson kept that byline, with Block added in. Even odder, a new book "by" Jill Emerson, Getting Off, appeared in 2011, in the middle of that burst of republication. And Block has said that Emerson was something of an alter ego -- a female persona that he saw in some ways distinct from his other, male, writing voices. So it's a little odd, but it does make sense -- writers create new people in their heads for a living, after all, and once in a while those people will write their own books.
I haven't read most of Block's old smutty books -- I vaguely intend to, but I vaguely intend to read a lot of things, and I don't own any of the Lord or Shaw books, which makes them pretty low on the pile. I did track down and read Ronald Rabbit Is a Dirty Old Man, the kiss-off to the smut-book business published under Block's name in the early '70s. And I did read Getting Off. I'm more interested in the Emerson books, maybe because they seem to still be a part of a current "career" and maybe because Block sees them as something distinct. Anyway, Threesome looked like the most "writerly" of the old Emerson books -- it's the story of what we now call a "stable triad," written round-robin by all three parties in their own voices -- so that was my next Emerson book.
The three are cartoonist Harry Kapp, his wife Priscilla (Pris) Kapp, and Pris's old college roommate Rhoda Muir. It's the late '60s, Harry is in his mid-thirties while the two women are a year or two shy of the big three-oh. Harry and Pris live in a house out in the woods in western Massachusetts -- close enough for Harry to get to NYC once a week to sell cartoons, far enough away to be quiet and, presumably, cheap. Pris and Rhoda were lovers in college, and Harry knows this, from the usual who-else-have-you-fucked-in-your-life pillow talk with his wife.
The curtain comes up with Rhoda typing -- the whole book is very much typed by the characters, and they comment on each other's revelations and opinions in what they say is their main current method of feedback -- as she explains how they came to start on the project of the book. (They saw that Naked Came the Stranger was a huge bestseller, and thought they could do at least as well with just three of them and a "true" story.)
The story itself is unsurprising and fairly generic: Rhoda was fleeing a bad Las Vegas divorce, came to stray with Pris for rest, and ended up sleeping with both Harry and Pris within a couple of days. There are some complications, and some other sex, both before and after the threesome got established -- got to keep things spicy! -- but that's basically it. They all got together, they started fucking, they're basically happy as the book ends.
It's not a whole lot of plot, even for a short novel, but it was enough for a paperback where the sex was the main draw, and shocking sex (which threesomes were, I guess) was even better. I am eliding some actual plot points here, of course -- "some complications" in the last paragraph basically yadda-yaddas the entire story, and much of the story takes place during the writing of the chapters, which is a nice device -- but it was always thin, and it's part of a genre of thin stories.
Block doesn't entirely give them completely different voices, though they are somewhat distinct in their tics and concerns. Again, he probably wrote this in a month to hit a publishing slot. No one ever expected fine literature from smut books. The sex is very much in a '60s context, and I thought it was clear the whole thing was written by a man, despite the "Jill Emerson" name on it originally. (For one example, the two women have a moment where they declare, semi-randomly, that of course their having sex together is sexy for Harry to contemplate or watch, but two men having sex together could never, ever be sexy for women. That's a man talking in the 1960s to an audience of other 1960s men.)
Threesome is modern enough that you could draw a through-line from it to newer books, but dated enough that it clearly takes place in a different world. I find books like that can be really interesting, as if they're circling some historical event horizon: still accessible but getting further and further away. It's not a major book in any way, but it's fun and professionally written and sexy in the ways it wants to be, so I'd say it's still a success, fifty years later.