This book presents the adaptation of lean principles to the precast construction industry to eliminate or minimize construction wastes, by modeling the precast construction process influencing manpower requirements. This is done using the shared mental models theory to understand how the lean principles enable people to work together to complete the tasks and work together effectively as a team throughout the entire precast construction process from the design, production and logistics to installation stages. Besides the theoretical concepts, this proposed book also presents the practical aspects faced by contractors through the conduct of questionnaire surveys to understand how the implementation of lean principles and shared mental models will affect the occurrence of construction wastes and hence the changes in the total man days used during the precast construction process. This book also presents a neural network model for developing leading indicators that classify precast construction projects in accordance with the manpower changes achieved through the construct of lean principles and shared mental models. This is to help the construction industry to predict the risk of low construction productivity and enable effective lean implementation to optimize the manpower effort required.