Originally published in 1902, this title was discovered as a manuscript after the author's death and was published 4 years later. David Kay published articles on various subjects and was one of the sub-editors on the eighth edition of Encyclopaedia Britannica. After writing an article on mnemonics he became very interested in the subject of memory. He had already published a title in 1888, Memory: What It Is, and How to Improve It, and this volume was intended to build on that discussion. A great opportunity to read one of the early discussions on human memory.