The Mathematics of Love by Emma Darwin
Two stories alternate through the book, seemingly very different, but inextricably linked by the end.
Major Stephen Fairhurst, maimed at the Battle of Waterloo, travels Europe, mourning his lost love and searching for meaning in his life. He befriends an independent-minded woman, passionate about photography.
Anna, a lonely teenager in the mid-seventies, is left to fend for herself one summer with unknown relatives. She is befriended by exotic neighbours, who help teach her about photography - and life. The themes of photography, independent thought and especially the importance of love for others, blend the two stories satisfyingly into one.