I am an enormous murder mystery fan and I have a particular fondness for Agatha Christie. To date, I’ve read about ten of her books and across the whole selection I’ve found her a tireless innovator, always tinkering with the formula of the murder mystery. Novels like The Murder of Roger Ackroyd are famous for this, but even Murder on the Orient Express, likely her best known work, defies the usual routine of a murder followed by a systematic investigation, a dramatic confrontation and a satisfactory conclusion. In both of those novels, too, relatively archetypical characters are more vivacious and compelling than they have any right to be as mere mystery puzzle pieces. So I was excited to read Sparkling Cyanide, a novel I picked up for the price of a coffee.