In the final volume of his historical neuroscience trilogy, prize-winning author Alan J. McComas recounts the research that led to recognition of the hippocampus, a structure deep within the brain, as being primarily responsible for memory. This intriguing and exciting account includes observations on patients with memory loss as well as insights from ingenious laboratory experiments. Using several arguments in support, McComas suggests that it is the electrical impulse activity of neurons in the hippocampus that creates consciousness and that the latter is, in fact, the ever-changing sequence of short-term memories. He show us how a deeper knowledge of the hippocampus can help us develop a fuller understanding of Alzheimer's disease and other disorders of memory and behaviour, including 'long COVID. Lavishly illustrated, Aranzio's Seahorse will be of value not only to neuroscientists, psychologists, and philosophers but to all those interested in the workings of the brain and in the history of its exploration.