If you are fascinated by Agatha Christie, or simply intrigued by the craft of constructing a whodunit, this is the book for you. John Curran, a long-time fan of the Queen of Crime, has been granted access by her family to an extraordinary collection of her private notebooks, 73 in all. He deciphered her handwriting, and set about piecing the information together, to produce a textbook example of literary sleuthing. One of the complications was that Christie scattered information about her works-in-progress across various different notebooks – jotting down ideas in whatever was to hand, it seems. Curran speculates on occasion, but such is his knowledge of the canon, and his empathy with Christie’s writing, that his comments invariably seem logical and soundly reasoned. It is fascinating to see how ideas evolved in her mind – sometimes over a period of years – before a particular book finally achieved publication. For instance, she originally thought of including Miss Marple, rather than Poirot, in Death on the Nile. There are countless other titbits that Christie fans will find intriguing, and as a fellow writer of whodunits, I was quite mesmerised by some of the insight into this remarkable novelist’s thinking. Two hitherto unpublished Poirot stories are included in the volume, and for many they will be reason enough to buy the book, although it has to be said there is usually a good reason why certain stories remain unpublished. But for me, the appeal of this book is Curran’s labour of love in making sense of the notebooks. I found it enthralling - the most enjoyable non-fiction book about the crime genre that I have read in a long time.