A key factor in successful application of Tunnel Boring Machines (TBMs) technology in tunneling is the ability to develop accurate performance estimates for determining project schedule and costs. Over many years of TBM related research, the Earth Mechanics Institute of the Colorado School of Mines (CSM) has developed a computer based model to predict the performance of TBM in hard rock. Although the CSM model has proven reliable in massive rock conditions, its accuracy has been limited in rock mass exhibiting a high degree of fracturing. Quantifying the rock mass fracture and intact rock brittleness effects into the CSM model, Modified CSM Model has been developed. This book named as “Modified CSM Model for Predicting TBM Performance in Rock Mass” is related to rock mass-TBM interaction. The book reviews the well-known TBM performance prediction models such as; Norwegian University of Science and Technology (NTNU), QTBM, CSM, and Modified CSM. Further, it includes geotechnical and technological information related to the projects used for development of the Modified CSM model. The book is useful for engineers and scientists who deal with rock mechanics and TBM tunneling.