Because of failing health, John von Neumann did not finish his last book, The Computer and the Brain. The book, issued posthumously in 1958, was a published version of the Silliman Lectures which von Neumann was invited to deliver at Yale in 1956. Although von Neumann prepared the lectures by March 1956, he was already too sick to travel to New Haven and could not deliver the lectures as scheduled. He continued to work on the manuscript until his death on February 8, 1957. The manuscript remained unfinished, as his widow Klara von Neumann explained in her preface to the posthumous edition.
Von Neumann's 82 page essay was divided into two parts. The first part discussed the computer: its procedures, control mechanisms, and other characteristics. The second part focused on the brain, systematically comparing the operations of the brain with what was then state-of-the-art in computer science. In what seems to have been the groundwork for a third part—but it was not organized as a separate part—von Neumann drew some conclusions from the comparison with respect to the role of code and language. Von Neumann wrote that "A deeper mathematical study of the nervous system may alter our understanding of mathematics and logic."