Their Little Secret, the latest in the Tom Thorne series of crime novels, offers further proof of why author Mark Billingham is probably the best crime writer in Britain today — and one of our very best writers, full stop. This complicated, deeply human story revolves entirely around an extraordinary woman named Sarah, who at the very start of the book appears as the next victim for a con artist named Conrad, but is actually so much more than that. In parallel with the Sarah and Conrad story is the ongoing struggle of DI Thorne to have a life outside of the Job. His fellow officer, Nicola Tanner, plans a key role in the story and her name now features in the series title. The only thing wrong with this book is that having devoured it in two days, I now have to wait a full year for the next book in the series.