Mónica Bustos was born in Asunción (Paraguay) in 1984. She began writing when she was nine and after the publication of her first novel, "León muerto" (Dead Lion), at eighteen she went on to publish a book of short stories, "Complejo de Bustos" (Bustos Complex) in 2004.

Family therapist, psycho-oncologist, expert in families and oncology, the author has a degree in psychology from the Universidad Central de Venezuela (UCV), and has completed a Masters in psycho-oncology at the Universidad Complutense de Madrid (2003-2005) and a Masters in systemic family therapy

Mónica Gonzalo Caballero is a psychologist and child and youth psychotherapist. She is a member of the board of directors of the clinical and health psychology department, and teacher at the Official College of Psychologists of Madrid.

Mònica Peitx is a Barcelona-based paediatrician specialising in endocrinology and nutrition. She wrote her first book, El cuento de Max' ('Max's Story') for overweight and obese children, in 2008.

Mónica Rodríguez was born in Oviedo (1996). She holds a degree in Physics and worked in research for fifteen years. In 2003 she published her first children's book. Since 2009 she has been totally dedicated to children's and young adult literature and has published more than a hundred books.