This book reports the findings of the first ever major investigation into the ways in which individual and group perceptions of competition impact on the development of strategy at the individual, group and industry levels of analysis. It is based on a study underatken in the UK residential estate agency industry, during a period of rapid change and draws extensively on one of the largest and most sophisticated datasets ever gathered in the field of managerial and organizational cognition to date. It is the first comprehensive logitudinal study of actors' mental modes of business competition, providing supporting evidence for key theoretical concepts and powerfully demonstrating why we need well-validated techniques to improve strategic thinking from a psychological standpioint. This book will be of interest to researchers and advanced students in the field of strategic management, organizational theory and behaviour, organizational psychology and marketing.