"A book that sweeps over the arguments that concern life and the great fundamental questions. Thoughts of a life and about life: on science and society; nature, history, the world's religions; love. An essential philosophy. Reflections based on emotions and memories, casual remarks: a panorama, a situation, a phrase spoken or heard, a conversation. The scientific method. Questions are posed and answers sought that may arise unexpectedly after years, when the brain, fully autonomous, decides to supply the connections. Perhaps travelling in the car: moments when the attention is distracted, between waking and sleeping." The book represents a path that makes up the life of a man, in particular the author's. Everything takes place around a central trunk, "a tree of life". A circle, a cycle, a path without end, an infinte journey different for every one of us but superimposed.