Claudio Naranjo's Ennea-Type Structures is a self-help manual based on the enneagram, a system of nine personality types.

The book, drawing on Naranjo's extensive experience and teachings from Oscar Ichazo, provides descriptions of each type's traits, motivations, and underlying psychological dynamics. Naranjo's approach integrates concepts from various psychological schools and esoteric traditions, emphasizing the role of "ontic obscuration," or a loss of being, in shaping personality. The text also includes forewords by E.J. Gold, who praises Naranjo's work and its unique contribution to self-knowledge.

Finally, the book offers suggestions for further self-exploration using journaling and meditative practices.