The book covers areas such as: general information about tunnels, historical development in tunnel construction, traditional tunnel construction methods before NATM, principles of tunnel construction according to NATM, classification of rock masses, stress conditions around excavations, securing underground excavations, excavation by blasting, excavation in soft rocks, portal structures, monitoring and ventilation during excavation. Additionally, the book presents eleven case studies from practice that the authors have analyzed, which cover similar or identical thematic areas as those addressed in the aforementioned book.