Several months ago, I purchased this novel. But it was only 3 weeks ago that I began to read it. From the moment I read the initial chapter which features the bedroom scene with Dexter ("Dex") and Emma ("Em") on the night after they both had graduated from university (July 15th, 1988), I WAS HOOKED. I developed such a deep empathy for both of them, though I was especially partial to Emma, who came from a humbler background compared to Dex.
Nicholls' plot device of focussing on the lives of both Dex and Em through the prism of July 15th from 1988 was very clever. I liked being able to see how both their lives developed over time.
As someone who graduated from college in 1986, I strongly identified with Dex and Em, because they are roughly of the same generation as myself. (There was one song that played itself in my mind like a refrain as I read deeply into this novel --- and it was, "SOMEWHERE IN THE WORLD (Someone's Thinking of You)" by the UK band Swing Out Sister.)
"One Day" is representative of the best novels that evoke a welter of emotions that will make the reader hearken back to his/her salad days and smile.