The hype surrounding STARZ’s new adaption of Outlander may come from the fact that it’s a new series by Battlestar Galactica‘s Ronald D. Moore, or that it stars the Internet’s new crush Sam Heughan, but what you may not know is that Diana Gabaldon’s Outlander series of historical novels has been around since the early ’90s — and that her take on raunch, romance, and time travel might just be feminism’s answer to Fifty Shades of Grey.

Before you give in to Fifty Shades of PTSD and run away screaming and crying, know that the Outlander series is not Twilight fan-fic, and there’s no tampon scene (promise). I first became familiar with the books as a progression of gigantic, door-stopping, forest-killing tomes that appeared in my mother’s beach bag and soon lined shelves that could barely withstand their weight. Soon, word got around that the series wasn’t just romantic… it was steamy. Sexy. Scottish. And it seemed to be everywhere. But while I picked up the Outlander books expecting a hot hero and plenty of damsel-in-distress moments, I had no idea that I was about to encounter a series of books that throw traditional romantic tropes out the window.

The series centers around the adventurers of Claire Randall, a post-World War II nurse who is reunified with her husband after the war only to be zapped away to bloody 18th century Scotland. There, she’s swept into a world of political intrigue, brutal misogyny, and a present in which she’s deemed a “Sassenach,” or Outlander. She’s eventually forced to marry Jamie Fraser, a redheaded soldier with a fiery past and a hot temper, and the books follow her as she juggles two husbands and careens back and forth between centuries, all while kicking some serious ass.

Let’s just get this out of the way: if you’re looking for hot Highlanders and plenty of scenes between the sheets, Outlander does not disappoint. Page one of the first book opens with our heroine in bed with her very giving husband, and by page three we’re asked to imagine what Scotsmen don’t wear under those kilts. This is a book with lines like, “If I were a horse, I’d let him ride me anywhere”; “Open your legs… I mean to be sure you’ll remember me while I’m gone”; and “I didna say I wanted an apology, did I? If I recall aright, what I said was ‘Bite me again.'” But while the books aren’t exactly stingy with the sex scenes, there’s more there than you might expect.

Gabaldon doesn’t give her heroine an easy row to — well — hoe. Claire’s got a Scotsman to tame, a new culture to acclimate to, and a time-travel mystery to solve. The 20th-century medical knowledge she brings to the 18th century allows her to save a lot of lives and ingratiate herself into the weird world of 1742, but it also makes people suspect she’s a witch. And Game of Thrones has nothing on the complex political action to be found among Scotland’s wild clans. As I read on, I became more and more intrigued by Claire, a woman who busts into a man’s world kicking, cussing, and refusing to be subdued. The series has sex and violence galore (including some way-problematic rape-y scenes and a husband-on-wife spanking that has polarized readers since the ’90s), but they’re approached from a female perspective — sans the male gaze. The books are genre-bending, but they’re gender-bending, too. Who needs Christian Grey when your main character is the provocateur, the one leaning back in her bed, appreciating a strapping Scottish man, and wondering if he’ll ever strap HER?

Sure, Jamie the hot Highlander has been well endowed in every sense of the word. But he’s not the catalyst in the Outlander books. In fact, he’s often the object of Claire’s frankly sexual gaze — and the receptacle of her dirty thoughts. When’s the last time you read a mainstream sexploration novel in which the man’s the virgin and the woman’s the instigator? Even though Claire submits to a sham marriage of convenience with Jamie (and despite a loving and plenty sexy husband at home in the 1940s), she doesn’t exactly keep him at arm’s length. In one of my favorite scenes, lusty Claire is horrified when she discovers that her new husband has been told that sex is about getting in, getting out, and getting on with life. Luckily, her libido is about the size of Scotland — and she’s willing to step in to teach Jamie a trick or two.

As hot as I am for men in tartan and over-the-top adventure, I think the secret of the series’ success is in its subtlety. There are no billionaire doms to see here, no wishy-washy Mary Sues to be seen. In fact, Jamie and Claire do the nasty (and everything else) like equals. And though its sex scenes are passionate, Outlander, with its outlandishly romantic take on time travel, intrigue, and split affections, does much more than bump and grind. I came for the sex, but I stayed for the modern heroine, the woman’s-eye view of a ferocious time, and the promise that it’s possible to kick ass even when all of the odds are against you. OK, I also stayed for the sex. And it turns out I’m not the only one seduced by the series’ potent brew of history, fantasy, and romance.

There are now eight books in the series (each volume so big I could kill my own highwayman with it), which has now sold over 20 million copies. Fans have evolved from CompuServe forums to sites called “Talk Jamie to Me” and “Outlander Addiction” and sold-out retreats. They even got so overwrought about the TV adaptation that they descended on a castle rumored to be a filming location before anyone had seen the show. And though Gabaldon has stirred up outrage by requesting that fans keep their fic to themselves (it hasn’t worked), the Outlander frenzy doesn’t seem to be cooling down any time soon. Maybe, like me, the books’ rabid fans are excited about a series that lets men — hot, hot Scottish men — play the object for once.