Exactly how steamy is this story?
NC-21
Okay, we know that's not a proper rating, but we're just looking out for you—because Kundera isn't. He has no problem confronting and including challenging sexual relationships in this work: from Karel and Marketa's threesomes with Eva to Jan's never-ending quest to relieve his sexual boredom and Barbara's orgies, there's plenty in this work to merit keeping it on a high shelf away from the kiddies.
Oh, yeah, and then there's all the sexual violence that Kundera depicts and that his characters fantasize about. Hugo essentially rapes Tamina because her revulsion turns him on; Jan says rape fantasies are an integral part of male arousal; and Kundera calmly explains how much he really wanted to violate his nice friend that one time. And we're not even sure what to call the shenanigans on the island of children.
Come to think of it, a high shelf might not be enough. You might want to lock this one up when it's not in use.