The Graveyard Book by Neil Gaiman
The Children's Bach by Helen Garner
Lord Hornblower by CS Forrester
Breath by Tim Winton
I find I can recommend all four of these books. Strangely enough, each of them has a theme connected with the idea of growing up.
Lord Hornblower by CS Forrester. Most people will be familiar with the Hornblower books of adventure on the high seas, of the English fighting the French during the Napoleonic wars. In Lord Hornblower, Hornblower is feeling a bit sick of Napoleon and the ongoing wars. The story begins with him comfortably in England with Barbara, but he is called away to resolve a mutiny on another ship. One thing leads to another, and Hornblower meets up with an old flame. Meanwhile, Napoleon is defeated and exiled. When Barbara leaves England for a convention in Europe, Hornblower races back to France to visit his old girlfriend. Then Napoleon returns and everyone's lives are in danger.
I couldn't help thinking that Hornblower's love life was a bit plot driven. Still, it's a good read, of course. It's probably Hornblower's predilection for introspection that makes these stories so accessible to those of us unfamiliar with things nautical and therefore so easy to read.