NOTE: As a work in progress, this list will be periodically updated to reflect my latest research.

Ever since my sister and I created our first imaginary world at age 4, I’ve been interested in imaginary worlds, technically termed "paracosms," and imaginary characters/friends. Information about the paracosmic is surprisingly difficult to come by, but, over the years, I have scraped together relevant material. Most of it is from a psychological, psychiatric or sociological point of view, although a few New Agey things have crept in since I considered them useful. Forthwith, a list.

Caughey, John. Imaginary Social Worlds: A Cultural Approach. In a welcome antidote to archetypical navel-gazing, Imaginary Social Worlds compares the contents of imaginary social worlds cross-culturally. Caughey examines daydreams, celebrity fantasies, sexual fantasies, etc., and looks at the ways in which an individual’s fantasy world reflects themes and obsessions of the world around him/her.

Cohen, David; MacKeith, Stephen. The Development of Imagination: The Private Worlds of Childhood. Containing one of the first longitudinal studies of children and their paracosms, this book is notable for collecting stats and stories about the paracosms of several score British paracosms and the lives of their creators. The best parts of this book give thumbnail sketches of each creator’s family circumstances [economic status, siblings, location] and how these affected each paracosm. Included is also a summary of the salient points of each imaginary world. Good for a look at the actual content of paracosms.

Matthews, Caitlin. In Search of Woman’s Passionate Soul: Revealing the Daimon Lover Within. A collection of observations from heterosexual women discussing their experiences of relationships with male imaginary characters. Despite its Jungian underpinnings, limited sample size and ridiculous extrapolation, I like this book for its first-person reporting about the paracosmic.

Root-Bernstein, Michele. "Imaginary Worldplay as an Indicator of Creative Giftedness." In The International Handbook on Giftedness, edited by Larisa V. Shavinina. Noting that the seeds and early signs of adult creativity may be seen in childhood play, Root-Bernstein looks at what childhood paracosms can tell us about their creators as adults. She notes a high correlation between creators of childhood paracosms and those who went on to be artists and successful scientists. Less about paracosms themselves and more about their implications.

Rowan, John. Subpersonalities: The People Inside Us. Dry, but good for a historical overview, this book discusses the changing conceptions of  imaginary characters over the last 150 years of psychology/psychiatry.

Taylor, Marjorie. Imaginary Companions and the Children who Create Them. Taking the perspective of a child development psychologist, Taylor synthesizes many studies on fantasy play in children. Discussing imaginary friends, transitional objects and paracosms, she concludes that the invention of these things represents a common, healthy aspect of modern American child development. Taylor is at her best when talking about imaginary friends; her section on paracosms has great first-person reports, but ends too abruptly.

Watkins, Mary M. Invisible Guests: The Development of Imaginal Dialogues. A premier introduction and overview to the concept of multivocal consciousness, imaginary friends, whatever you want to call it. Watkins argues that the current psychiatric fixation with a unitary voice/self ignores a rich philosophical, mythological and phenomenological tradition of an internal population of >1. To that end, she synthesizes information reaching back to ancient Greek epics and forward to modern Jungianism. Her discussion of authorial relationships to story characters is especially strong.

Watkins, Mary M. Waking Dreams. Written before Invisible Guests, this book takes the same pro-paracosmic viewpoint, extended to fantasy, daydreaming, waking dreams and other supposedly "non-productive" states in general. Watkins’ Jungian background leads her to champion the concept of "active imagination," that is, calling out the characters in one’s head and talking to them. She explores the origins of this technique in European and American practice. Less rigorous and more poetically written than Invisible Guests, Waking Dreams is a thought-provoking ancillary, but should be read after Invisible Guests.

Wegner, Daniel M. White Bears and Other Unwanted Thoughts: Suppression, Obsession and the Psychology of Mental Control. A lucid, conversational, funny book about the ways in which people attempt to control their thoughts and the ways in which these methods backfire. Wegner’s comments on suppression and obsession provide insight into how people can create characters and then endow them with so much personality that they seem independent.