Night Over Water, by Ken FollettRead about another entry on the list.
Fascists, clipper planes, and jewel thieves make for excellent window dressing. This bestseller was foundational for being the first book I ever read—and read, and read—featuring explicit sex scenes. If you want your tween to learn early on that there are more ways to be intimate with a partner than intercourse, and that communication between partners is both key and super hot, slip her this paperback. Neither of you will be sorry.