"Any Human Heart" is a novel by William Boyd that follows the life of Logan Mountstuart, a fictional character whose experiences span much of the 20th century. The story is presented through a series of journal entries, revealing his relationships, ambitions, and the historical events that shape his life. The narrative explores themes of love, loss, and the passage of time, as Logan navigates various personal and professional challenges. The book also reflects on the nature of memory and identity, offering insights into the human condition through Logan's introspective journey.