The book is the rare and delightful work of philosophy that is both lightly and playfully written, while at the same time being patient, perceptive, and careful. If that's you're kind of thing, you'll like it.
Blackburn makes no apologies for his disinterest in theological or religious claims, and at least does the religious reader the courtesy of admitting it. He participates in the commonplace blaming of St. Augustine for some of the difficult relationship of Christianity and sex, though I have to admit that his treatment of the doctor gratiae is much more fair and accurate than what one usually hears. He captures a lot of Augustine's nuance, and makes the important point that Augustine was a moderate in his own context.
What you won't get from this book is the spiritual good news of sexual desire: our hearts--and our bodies--spontaneously reach out for another, for connection, for communion. In this energy is the beginning of prayer, of the drive for the Other Itself: the mysterious Other we call God.
On the other hand, despite his stated disinterest in spiritual claims, Blackburn comes pretty close to this good news in his refutation of the idea that sex demands privacy because it is shameful:
Embarrassment arises because when we are looked upon or overheard by someone else, there is a complete dissonance between what they witness--infantile prattlings, or, if their gaze is obscene, just the twitchings and spasms of the bare forked animals--and the view from the inside, the meanings that are infusing the whole enterprise. (102)
Great English, no? The book is almost worth it just for sentences like this one, of which there are many.