Few things are as essential to our lives-and as apparently unfathomable-as our memories. As Jane Austen's heroine Fanny Price remarks in "Mansfield Park," "if any one faculty of our nature may be called more wonderful than the rest, I do think it is memory . . . sometimes so retentive and so serviceable, so obedient-and at others so bewildered and so weak."

In Memory, David Samuel draws on a lifetime of scientific research to produce an informative and wide-ranging view of the subject. He examines how memory has been investigated in the past and what modern studies of brain structure...