Mmm, happiness is a new series to read. I've been hearing good things about Laurie R. King's Mary Russell/Sherlock Holmes stories for a long time, and finally managed to pick up the first one, The Beekeeper's Apprentice (Picador). It's good, and what's even better is that there are a whole bunch more books to be read!
In the character of Mary Russell, King provides a good foil for the semi-retired Sherlock Holmes: their witty banter and intelligent conversation are what make this such a fun and clever read. I wasn't sure a teenage girl would be able to hold her own with Holmes, but Russell manages it. King knows her Holmes canon, and is able to complement the original stories with remarkable dexterity (and good-naturedly skewer them when necessary, too).
Reasonably suspenseful, this volume provides a good introduction to the Holmes/Russell partnership, and I'm very much looking forward to seeing where the next volumes will lead.