Virtual reality is now synonymous with digital adventure and immersion, but its journey began a long time ago, at the intersection of science, mathematics, and the human desire to transcend the limits of the physical world. In this book, we will explore how virtual reality, a technology that seems futuristic, actually has its roots in centuries-old mathematical and psychological concepts, brought to life by the constant drive for innovation and discovery. We will begin with a historical overview, from the birth of the first visual simulation devices to the fundamental discoveries that transformed ideas of computation and representation into digital worlds. From pioneers like Ivan Sutherland, who dreamed of building the first "virtual reality display" in the 1960s, to today's advances in neuroscience, we will uncover how VR has become a bridge between imagination and the tangible, constantly pushing further. But virtual reality is not only a technological or entertainment field. In recent decades, it has become a revolutionary therapeutic tool, offering treatments for phobias, post-traumatic disorders, and chronic pain. Thanks to VR, patients can confront their fears or immerse themselves in calming environments, exploring healing possibilities once thought unimaginable. The technology proves to be a powerful ally for psychology, offering solutions based on gradual exposure and emotional control. Finally, we will delve into the complex mathematical and algorithmic calculations that make VR possible: from the geometry of virtual worlds to the modeling of movements and interactions. Virtual reality is based on sophisticated algorithms designed to generate realistic environments and accurate real-time responses. We will discover how these mathematical foundations influence interactivity and the precision of simulations, laying the groundwork for the future of VR. This book is a journey through the past, present, and future of virtual reality, viewed through the prism of history, therapy, and mathematics, exploring a technology that does not merely imitate the world but recreates it and, in some cases, improves it.