Since moving to Canada in 1969, Jane Jacobs, who recently passed away, has inspired and continues to inspire debate within Canada, as well as elsewhere, on the potential for and promise of the urban experience. Jacobs was not only a critic of unrestricted growth and the destruction of neighborhoods but, frequently, of the efforts of urban planners. The exchanges between Jacobs, author of The Death and Life of Great American Cities (1961), and the American planner and cultural critic Lewis Mumford, author of The Culture of Cities (1938) and The City in History (1961), raised some important issues that are still debated. In spite of their differences, however, the two also shared many values, even if each had reservations about the likely efficacy of the other's policy prescriptions. This paper compares and contrasts the views of the two authors who shared a concern about the hazards of unfettered growth but who often differed not only on what the response to growth should be, but also on the proper approach to understanding how cities either work or do not work.