First of all, while the book does cover a lot of ground—the anti-hero, Paul, has two sex partners of different races than his; there's also a surprise lesbian, a neglected alcoholic wife and statutory rape that's presented as nothing but healthy, uninhibited good times—there is no sex marathon at any point (though Paul goes at it with enough frequency and energy that there sure could be).

Orgies are talked about but only occur theoretically, off page, and don't include Paul. The scene on the front cover is not in the book.

What is in the book? Paul marries a woman to manipulate her brother-in-law into promoting him from stock boy to purchasing agent at a corporation that deals in metal products.

There's no ceiling to Paul's lust for advancement, money and sex, however, and he's soon setting up his superiors to fall so he can take their place higher up the corporate ladder. And then he also wants to have sex with his secretary so that happens a bunch.

Numerous other conquests, both sexual and professional, happen about once in each chapter. Paul takes a lot of risks and manages to make sure they pay off. There doesn't seem to be an endgame, just more money, more sex, more power.

It's a very American novel and while not exactly a satire or critique of business-world values and their concomitant depravities, it's not that far away from being that. It's also well written and zips along.

Whoever wrote it had no need, expectation or, presumably, desire to be coy or judgmental. Paul tells his story in the first person and is simply telling us what he does and why he does it. He's a sex fiend, a sociopath, a user and destroyer of people and he has nothing to say about it other than that this is who he is and what he's doing.

I'm not going to say you should drop what you're doing and read this book (though the text is available online), but as far as mid-century(ish) acid-pen portraits of corporate life and its concomitatn sex culture go, Sex Marathon is approximately a zillion times better than the movie The Apartment.