"They were young, educated, and both virgins on this, their wedding night, and they lived in a time when a conversation about sexual difficulties was plainly impossible. But it is never easy."
McEwan shows a lot of constraint in On Chesil Beach. He lays out his subject matter rather plainly in the opening line of the novel, and then moves deliberately towards the inevitable conclusion. McEwan intersperses scenes of the wedding night with flashback that explain these two wonderfully crafted characters and the peculiar realtionship that they engage in. And why. While sex and sexuality are obviously important in the novel, don't expexct anything gratuitous. More than sex this story is about, in the immortal words of Axl Rose, "failure to communicate". Not only are they not truthful to each other, but they are also unable to be true to themselves.
Thematically McEwan isn't breaking any new ground, but his rigor and pacing are a sight to be admired. This isn't an epic story, but it is exquisite in its execution.