Since their first emergence in the work of Paul David thirty years ago, the dual issues of Path Dependence and Lock-In have become critically important subjects in the fields of economics, sociology, and business strategy. Theoretical and public policy debates on these issues have arisen, addressing whether markets consistently choose the best products. This collection presents each side of the debate, bringing together key publications that initiated this literature with the later works that criticize or defend many of the early claims. Both the theoretical and empirical foundations of Path Dependence and Lock-In are examined along with the role of network effects. An original introduction by the editors is included to situate each article in its wider context.