Little's Law as Viewed on Its 50th Anniversary

Fifty years ago, the author published a paper in Operations Research with the title, "A proof for the queuing formula: L = lambda W" [Little, J. D. C. 1961. A proof for the queuing formula: L = lambda W. Oper. Res. 9(3) 383-387]. Over the years, L = lambda W has become widely known as "Little's Law." Basically, it is a theorem in queuing theory. It has become well known because of its theoretical and practical importance. We report key developments in both areas with the emphasis on practice. In the latter, we collect new material and search for insights on the use of Little's Law within the fields of operations management and computer architecture.