The Unlikely Pilgrimage of Harold Fry

I just read Cynthia Korzekwa's review of this 2012 novel by Rachel Joyce and have added it to my reading list.  I'd never heard of it but my husband (Harold) also recommends it.

"When Harold Fry nips out one morning to post a letter, leaving his wife hoovering upstairs, he has no idea that he is about to walk from one end of the country to the other.
He has no hiking boots or map, let alone a compass, waterproof or mobile phone. All he knows is that he must keep walking. To save someone else's life."