The book portrays the ancient history of Cannabis sativa in its cultural and therapeutic aspects, providing the reader with relevant information on the scientific milestones of the discovery of the endocannabinoid system and phytocannabinoids, in particular cannabidiol (CBD), the plant's main non-psychoactive constituent, which has, among its many effects, an extraordinary anti-epileptic action against drug-resistant seizures. The book also explores the context of Epilepsy, a neurological disease that causes organic, psychological and social damage and affects thousands of people worldwide, bringing to light the scientific contexts that support the powerful anticonvulsant and neuroprotective action of "endocannabinoids", thus providing more quality of life for patients who still suffer from this "great evil of society".