Rather than attempting to cover all the aspects of consciousness (self-awareness, thought, imagination, perception, etc.), Crick focuses on the primate visual system and breaks down the prerequisites for conscious experience into several broad subconditions, including some sort of short-term memory and attention mechanism. The book then delves into a brief overview of many neuroscientific topics, ranging from a survey of how neurons function to a description of basic neural circuits and their artificial equivalents. Throughout, Crick cites various experiments which illustrate the narrow points he is making about visual awareness, such as studies investigating the phenomenon of blindsight in macaques.