Ernst Katz was one of the foremost teachers of anthroposophy in America during the second half of the twentieth century. He was professor of physics at the University of Michigan and, quite likely, the only professor in the country who taught courses in both natural science and 'spiritual' science at the university level. In the early 1960s, Dr Katz began writing his 'teaching essays', his response to the many questions through the years intended to help students comprehend the profound wisdom contained in the major works of anthroposophy. Core Anthroposophy makes these essays available, offering present and future students of anthroposophy with a valuable and accessible resource for better understanding the esoteric teachings of Rudolf Steiner.