The cuckoo is a unique species of bird in that the egg of a cuckoo is laid as an invader in the nest of another bird species. Once the parasitic cuckoo chick, before the other infant chicks (not the cuckoo's real siblings), has hatched, it slowly executes the others, by pushing their eggs from a high height, out of the nest, where they meet their demise in the grass below. The cuckoo does this in order to ensure that it is cared for by its adoptive mother; it is seeking this care and love of which it would be deprived if it had not murdered the children of the bird whose nest it had invaded. 
 I made the error of judging this book as a "common-place" murder-mystery novel at the half-way point, long before the book had even begun to climax. I've learned that, especially in the case of the murder-mystery crime genre, judging a book before the end is a grandiose mistake. The gloriousness of the book stems from the fact that the premise of the novel can appear so textbook throughout the beginning, only to reveal in the last few chapters that, in fact, it is no such thing. 
 I am no jaded judge of the murder-mystery genre, but in my relatively inexperienced opinion, The Cuckoo's Calling is gloriously written, and magnificently executed.