The School of Venus
The School of Venus, or The Ladies Delight was originally published in 1680 as erotica, complete with illustrations. This book is a simple but adult read, and not for those easily offended by language.
In many ways this is much more than "a dirty book" and a fun read. Written as a conversation between two women; fidelity, marriage, beauty standards, and social expectation are all discussed at different points.
A prominent Admiral and Parliamentarian of the age, Samuel Pepys wrote about this book in his journal. Among other things, he said "It was not amiss for a sober man once to read over to inform himself in the villainy of the world... it did force my prick beyond stand all the while."