Santiago Ramon y Cajal was among Spain's greatest scientists. A century ago, his work laid the foundations for the field of modern neuroanatomy. In 1906 Ramon y Cajal shared the Nobel Prize with the Italian anatomist Camillo Golgi for the development of the revolutionary neuron theory, which established the neuron as the basic unit of the nervous system. Born in Petila de Aragon in rural northeastern Spain, Ramon y Cajal was a bright but restless child and a poor student. His father, a surgeon, apprenticed him to a barber and later to a carpenter because he showed little academic promise. Both of these apprenticeships were failures. Surprisingly, Ramon y Cajal was admitted to the medical school at the University of Zaragoza, graduating in 1873. Upon receiving his license to practice medicine, he went to Cuba and worked as an army surgeon. In 1875 Ramon y Cajal returned to Spain, married, and became a professor at the University of Zaragoza. There, he began his neuroanatomical research, which became his main interest. Soon after, he was promoted to the rank of Extraordinary Professor and then to the directorship of the University's Medical Museum. In 1887 he became Extraordinary Professor at the University of Barcelona. In the following year, he published his first significant work on the nervous system, an analysis of the structure and development of the cerebral cortex. In 1892 Ramon y Cajal accepted the position of chairman of the Department of Histology and Pathological Anatomy at the University of Madrid. In 1922 he formally retired from the University but continued to conduct research, teach, and write his final book, The World Seen at Eighty: Impressions of an Ateriosclerotic.