O is for Outlaw is the fifteenth in the Kinsey Millhone mystery series by Sue Grafton.
First there was a phone call from a stranger, then a letter showed up fourteen years after it was sent. That's how I learned I'd made a serious error in judgement and ended up risking my life . . .'
The call comes on a Monday morning from a guy who scavenges defaulted storage units at auction. Last weekend he bought a stack. They had stuff in them - Kinsey stuff. For thirty bucks, he'll sell her the lot. Kinsey's never been one for personal possessions, but curiosity wins out and she hands over a twenty (she may be curious but she loves a bargain). What she finds amid childhood memorabilia is an old undelivered letter.
It will force her to re-examine her beliefs about the break-up of her first marriage, about the honour of her first husband, about an old unsolved murder. And it will put her life in the gravest peril.