Abstract
Different ages of humanity have required different modes of thinking. These modes aren't only reflections of the particular circumstances of life in each age; they're also projections of the forces that propel us to the next. The Web extra at https://youtu.be/0-kwid5kUAU is an audio podcast of Grady Booch's On Computing column, in which he discusses how we have progressed from the Cognitive Revolution to the Agricultural Revolution to the Industrial Revolution and now find ourselves in the Computational Revolution.