The New York Times billed it as a revolution, with the headline “New Navy Device Learns By Doing”, and The New Yorker similarly admired the technological advancement. Research on comparable devices was also being done in other places such as SRI, and many researchers had big expectations on what they could do. The initial excitement became somewhat reduced, though, when in 1969 Marvin Minsky and Seymour Papert published the book “Perceptrons” with a mathematical proof about the limitations of two-layer feed-forward perceptrons as well as unproven claims about the difficulty of training multi-layer perceptrons. The book's only proven result—that linear functions cannot model non-linear ones—was trivial but the book had nevertheless a pronounced effect on research funding and, consequently, the community. After research on neural networks returned to the mainstream in the 1980s, new researchers started to study Rosenblatt's work again. This new wave of study on neural networks is interpreted by some researchers as being a contradiction of hypotheses presented in the book Perceptrons, and a confirmation of Rosenblatt's expectations. The Mark I Perceptron, which is generally recognized as a forerunner to artificial intelligence, currently resides in the Smithsonian Institution in Washington D.C. MARK 1 was able to learn, to recognize letters, and could solve quite complex problems. Rosenblatt's Book Rosenblatt's book Principles of Neurodynamics: Perceptrons and the Theory of Brain Mechanisms, published by Spartan Books in 1962, summarized his work on perceptrons at the time. The book is divided into four parts. The first gives an historical review of alternative approaches to brain modeling, the physiological and psychological considerations, and the basic definitions and concepts of the perceptron approach. The second covers three-layer series-coupled perceptrons: the mathematical underpinnings, performance results in psychological experiments, and a variety of perceptron variations. The third covers multi-layer and cross-coupled perceptrons, and the fourth back-coupled perceptrons and problems for future study. Rosenblatt used the book to teach an interdisciplinary course entitled "Theory of Brain Mechanisms" that drew students from Cornell's Engineering and Liberal Arts colleges. Rat brain experiments Around the late 1960s, Rosenblatt began experiments within the Cornell Department of Entomology on the transfer of learned behavior via rat brain extracts. Rats were taught discrimination tasks such as Y-maze and two-lever Skinner box. Then their brains were extracted and injected into untrained rats that were subsequently tested in the discrimination tasks to determine whether or not there was behavior transfer from the trained