This book describes the general properties of the most popular liquid crystal (LC) phases nematics (Ns) and smectics (Ss), and in addition, is directed to fill in a niche of the LC field. This book covers topics ranging from the types and classifications of liquid crystals to a detail description of the fundamental properties of nematics and smectics, including continuum theory, non-linearity, behaviour in electric field, surface alignment, phase transitions, defect and textures and provides a useful reference intended for advanced topics of the physics of liquid crystals.