This book presents information about TMDC materials. Layered (lamellar) structure solids of transition metal dichalcogenides have been extensively studied. Transition metal dichalcogenides exhibit fascinating properties due to their van der Waals bonded layered structure, including charge density wave instabilities. Layered transition metal dichalcogenides (TMDC) of the type MX2 (M= metal atoms and X = chalcogen atoms) exhibits interesting physical and structural properties as have been reviewed by some leading scientists. TMDC have various characters of metal, semiconductor and magnetic substances and have been widely studied. The TMDC of MX2 type are layered compounds consisting of sandwiches with strong covalent/ionic interlayer bonds and weak van der Waals interalayer interactions. The information given in this book titled "Existing Information on MX2 Single Crystals" is the 1st part of series of books.