Principles of Nanoscience and Nanotechnology in the First part introduces the systematic development of materials and its long journey to nanodimensions and how nano has moved from the world of the future to the world of the present is discussed in detail. The Second part of the book emphasises on how the unique properties of nanomaterials have motivated researchers to develop simpler and inexpensive techniques to produce nanostructures of technologically important materials using both top down approaches which rely on continuous breaking up of the bulk matter and bottom up approaches which build the nanostructures by its constituent units. Both these approaches have been discussed in detail. Part Three of the book introduces the invention and development of sophisticated equipment for the characterization, measurement and manipulation of nanomaterials i.e., Atomic Force Microscope to study the nanomaterials down to atomic scale. The Fourth part describes the significant impact on almost all industries and all areas of society which will offer better built, longer lasting, cleaner, safer and smarter products for home, communication, medicine, transportation, agriculture and for industry in general.