Grimes main character is Superintendent of Scotland Yard Richard Jury that has trouble with his boss and a heart for odd little kids. A precocious kid is a staple in all of Grimes' novels. I love this addition they a depth of innocence even when the kid isn't that innocent.
The other main character in the books is Melrose Plant, a wealthy man who has given up his English titles and now leads a life of luxury. But Plant is also wicked smart, so once he meets Jury they two team up on various cases.
One of the other things I love about Grimes' writing is her use of literature through out her novels. She takes her two well read characters and has them thinking of lines they read as they view cases and life. That is so much of how I see the world, that this part resonates with me.
This is a long series and not all the books are equally good, but enough are that make it worth it. Also she is still writing which means the series isn't done yet. A heads up you have to start at book one, after that it doesn't matter but book one sets the characters. I tried to first read this series at book three and was very lost. You can easily find book one at most used book stores.