The Red Book: Liber Novus is a folio manuscript so named due to its original red leather binding. The work was crafted by the Swiss psychiatrist Carl Gustav Jung between 1914 and about 1930. It follows, records and comments in fair copy on the author's psychological observations and experiments on himself between 1913 and 1916, and draws on working drafts contained in a series of notebooks or journals, now known as the Black Books. Jung produced these beginning in 1913 and continued until 1917. Despite being considered as the origin of Jung's main oeuvre, it was probably never intended for conventional publication and the material was not published nor made otherwise accessible for study until 2009.

Carl Gustav Jung was a Swiss psychiatrist and psychoanalyst who founded analytical psychology. He was a prolific author, illustrator, and correspondent, and a complex and controversial character, perhaps best known through his "autobiography" Memories, Dreams, Reflections.