This book explores the atmospheric issue from a connotatively architectural perspective. It is a journey through the maze of atmospheric poetics, articulated in five stages. The first portrays the atmospheric vocation of the architectural experience, unfolding its impalpable essence; the second reconstructs the genealogy, evolution, and semantic geography of the word "atmosphere", focusing on the architectural niche; the third maps a taxonomy of definitions and design approaches on atmosphere forged over time by the architectural culture; the fourth discusses the current atmospheric turn that inflames architecture; and the fifth provides a new architectural theory of atmosphere of an experiential nature, informed by phenomenological, embodied cognition, and (neuro)biological principles. Atmosphere becomes the key to our empathic relationship with the physical world, capable of orchestrating a space-time continuum of emotions, body, brain, mind, and architecture.