A lot of series lose steam as they go along, but this one keeps getting better. This is book four in the "Wild Seasons" series, and it's better than book one, "Sweet Filthy Boy," though connected to that story more than the subsequent books in the series. Each book stands alone, but it will probably be a little more satisfying if you read at least "Sweet Filthy Boy" first, because that book introduces Mia, who is the ex-girlfriend of the hero, Luke, of this one.
"Wicked Sexy Liar" is a Reformed-Rake/Taming-of-the-Manwhore story. Five years ago, Luke broke up with Mia, his high school sweetheart, and went a little crazy on the rebound. He's spent the interim having lots and lots and lots of casual sex, and when he meets London, that's what they're both looking for.
Of course, London's got a magical hooha, and as soon as Luke hooks up with her, he can't get enough, but she has good reasons for wanting to keep things casual, especially when she realizes Luke is her friend Mia's ex. (Because friends' exes are, of course, off limits.)
The entertainment of the Manwhore-Taming trope usually stems from watching the hero get his comeuppance, after years of dismissing clingy women, in finally finding himself in the role of the Clinger rather than Clingee. "Wicked Sexy Liar" does the same, but even though it isn't groundbreaking, it's entertaining. Christina Lauren does snappy dialogue really, really well, and the secondary characters are well developed and contribute to the story (rather than merely being scenery in it -- yet another reason to read the series in order, though again, this would stand alone).
I loved Luke's relationship with his sister Margot, and I love how smart and sassy and grounded London is as a heroine. The ending of this book was a little too abrupt, but still emotionally satisfying, and the first 4/5ths of the book were great fun.