Preface -- Chapter 1: Progress on the Theoretical Study of Two-Dimensional MoS2 Monolayer and Nanoribbon -- Chapter 2: Electronic Structure of Exfoliated MoS2 -- Chapter 3: Tunable Electronic and Dielectric Properties of Molybdenum Disulfide -- Chapter 4: Ab initio study on MoS2 and its family: Chemical trend, band alignment, alloying and gap modulation -- Chapter 5: MoS2: A first principles perspective -- Chapter 6: Mechanical properties and electric field screening of atomically thin MoS2 crystals -- Chapter 7: Insights into vibrational and electronic properties of MoS2 using Raman, photoluminescence and transport studies -- Chapter 8: Optical characterization, low-temperature photoluminescence and photocarrier dynamics in MoS2 -- Chapter 9: The Application of nano-structure MoS2 materials in energy storage and conversion -- Chapter 10: Valley Polarization in Transition-metal Dichalcogenides by Optical Pumping -- Index.