Cook's third-person narrator is omniscient, telling what the characters are thinking but providing little explanation as to how they have come to think that way. Another Cook technique is to casually intersperse key clues with insignificant medical details, keeping the reader's mind churning as it tries to sort things through and find a focus.

Cook's most interesting and oft-used technique is the repetition of allusions to a facility or institution which, shrouded in mystery and surrounded with security against the outside world, seems linked to the ongoing crimes. Both the protagonist and the reader crave to sneak inside, snoop around and finally solve the puzzle.

In Coma, the mysterious facility is the Jefferson Institute, an intensive care facility for comatose patients. Inside, Susan Wheeler discovers that the intensive care is administered by a mainframe computer that continuously monitors each patient's bodily functions, automatically making adjustments to maintain homeostasis...