This book presents and introduces ellipsometry in nanoscience and nanotechnology making a bridge between the classical and nanoscale optical behaviour of materials. It delineates the role of the non-destructive and non-invasive optical diagnostics of ellipsometry in improving science and technology of nanomaterials and related processes by illustrating its exploitation, ranging from fundamental studies of the physics and chemistry of nanostructures to the ultimate goal of turnkey manufacturing control. This book is written for a broad readership: materials scientists, researchers, engineers, as well as students and nanotechnology operators who want to deepen their knowledge about both basics and applications of ellipsometry to nanoscale phenomena. It starts as a general introduction for people curious to enter the fields of ellipsometry and polarimetry applied to nanomaterials and progresses to articles by experts on specific fields that span from plasmonics, optics, to semiconductors and flexible electronics. The core belief reflected in this book is that ellipsometry applied at the nanoscale offers new ways of addressing many current needs. The book also explores forward-looking potential applications.This book examines ellipsometry in nanoscience and nanotechnology. It delineates the role of the non-destructive and non-invasive optical diagnostics of ellipsometry in improving the science and technology of nanomaterials and related processes.Preamble.- Preface.- A Brief History and State of the Art of Ellipsometry.-Advanced Mueller Ellipsometry Instrumentation and Data Analysis.- Data Analysis for Nanomaterials: Effective Medium Approximation, its Limits and Implementations.- Relationship between Surface Morphology and Effective Medium Roughness.- Plasmonics and Effective-Medium Theory.- Thin films of Nanostructured Plasmonic Noble Metals.-? Spectroscopic Ellipsometry on Metallic Gratings.- Mueller matrix applied to nanostructures.- Spectroscopic Ellipsometry and l3<