I WAS FIFTEEN when I first met Sherlock Holmes, fifteen years old with my nose in a book as I walked the Sussex Downs, and nearly stepped on him.

So begins the first of Laurie King's Mary Russell/Sherlock Holmes mysteries. I first read this book fifteen years ago, and enjoyed it enormously. It was during a mystery phase, when I was reading Elizabeth George and P.D. James and Martha Grimes.

I have had many reading phases, and I have had - as hard as this seems to believe now - extended periods of time when I read very little, especially those years when my children were small and my life was one child-centered event after another. 

When I read it the first time, I appreciated it as a mystery, and as a story. But I had not read any of the canon, and my knowledge of history was sketchy at best. Much of what makes this book such a remarkable feat escaped me. I knew I liked it.

Reading it this time, though, the book is the same, but I am completely different. In those intervening years, I've grown a lot as a reader, and my appreciation of Laurie King's craft is much more sophisticated. I've read most of the canon, and I can see the incredibly deft and practiced hand with which she fits this book into the canon, into history, into the interstices in the Holmes, Watson, Mrs. Hudson relationships. Into the world. The historical details are amazing, of Oxford, of Britain in the immediate aftermath of WWI.

"The year begins with Michaelmas term and the autumn closing in, when minds and bodies that have ranged free during the summer are bent again to the life of academe. Days grow short, the sky disappears, the stones and bricks of the city become black in the rain, and the mind turns inward to discipline. In Hilary term winter seems eternal, with the barest hint of lengthening days and the first sprouts of new life, but with the return in May for Trinity term the sap rises strong with the sun, and all one's energies are set to flower in the end-of-the-year examinations.

Of the terms, my favourite is that of Michaelmas, when the mind is put hack into harness and the wet leaves of autumn lie thick in the streets."

I am there, among the dreaming spires, in the year 1919. There is nothing heavy-handed about the way she builds Mary's world. And, even though this is mystery, in a really compelling way, it is written like the most immersive and fully-realized fantasy.

The mystery itself is fine. Buy it is Mary Russell and Sherlock Holmes and their relationship that is, for me, the most delightful aspect of this book. The way that they interact with each other, and the way that Mary, feminist, bluestocking, brilliant, rich, interacts with her world, these are the reasons that I will return to this book again and again.

"I became, in other words, more like Holmes than the man himself: brilliant, driven to a point of obsession, careless of myself, mindless of others, but without the passion and the deep-down, inbred love for the good in humanity that was the basis of his entire career. He loved the humanity that could not understand or fully accept him; I, in the midst of the same human race, became a thinking machine."

I'm not going to spoil the ending, because no one should ever reveal the solution to a mystery novel in a blog post. That's just terrible form. But whether you like mysteries or not, this is a book worth reading. It's brilliant. Truly.