U is for Undertow revisits the technique used in S is for Silence, namely, mixing Kinsey's current day narration with the narrative of the past.  This is a technique that works well for Grafton.

Kinsey is hired by a young man who's memory has been sparked by an article he reads in the paper about an old kidnapping. He doesn't have much to go on but thinks he might have seen something at the time.  With almost nothing to go on, he wants her to help him figure out if what he saw is relevant. Kinsey once again shows us the ins and outs of a good detective's work.  I find that aspect quite interesting.  The clues are almost non-existent and yet she manages to make something coherent out of them.  

The other thread running through the story is her almost-reunion with her family.  She finds out more in this book about the relationship between her mother and her grandmother than in any previous book.  The way it is being played out is quite interesting to me.

What I have found in the last several books, probably starting with Q is for Quarry, is that I am feeling more emotionally attached to the characters than I was in the previous books.  Not just Kinsey, Henry and Rosie but the characters of whatever mystery she is investigating.  I don't know if that's because when you are this far into a series, it all feels so real or if Ms. Grafton just keeps getting better at what she's doing.  I just know that particularly since Q I've been living in Kinsey's world.