Russell Ackoff's long and distinguished career as the doyen of Design and Systems Thinking was built around a collection of deceptively simple-but often overlooked-principles and observations. In Differences That Make a Difference-the last of his many books-Ackoff determined to distill the wisdom of a lifetime into a "glossary" that would be easily accessible to managers, employees, students, and academics alike. His aim was to dissolve (not solve or resolve) some of the many disputes in professional and private life that revolve around meaning and (mis)understanding. For example, development...