In recent years, there has been an increase in those, scientists or not, who claim that loneliness along with depression will very soon become the great epidemics of the 21st century. The phenomenon of loneliness has intensely occupied, over the centuries, art, philosophy, and literature, and in our days, the social sciences, mainly applied sociology. Contrary to what one might expect, there are not many studies by mental health professionals such as psychologists, psychiatrists, and psychotherapists, most of whom focus and overemphasize the pathology and painful consequences of loneliness. However, as a counterbalance, there are studies, such as those by the leading psychoanalyst Donald Winnicott, which refer to the individual's ability to be alone, considering that this ability is one of the most important signs of maturity in emotional development and contributes to human independence and creativity.

In this volume, we present the three most important, now classic, psychoanalytic approaches to loneliness, which are complemented by two newer studies that explore the potential benefits of solitude from the perspective of psychoanalysis, spirituality, and social psychology.