This book presents the state-of-the-art of optical remote sensing applied for the generation of marine climate-quality data products, with contributions by international experts in the field. The chapters are logically grouped into six thematic parts, each introduced by a brief overview. The different parts include: i. requirements for the generation of climate data records from satellite ocean measurements and additionally basic radiometry principles addressing terminology, standards, measurement equation and uncertainties; ii. satellite visible and thermal infrared radiometry embracing instrument design, characterization and, pre- and post-launch calibration; iii. in situ visible and thermal infrared radiometry including overviews on basic principles, technology and measurements methods required to support satellite missions devoted to climate change investigations; iv. simulations as fundamental tools to support interpretation and analysis of both in situ and satellite radiometric measurements; v. strategies for in situ radiometry to satisfy mission requirements for the generation of climate data records; and finally, vi. methods for the assessment of satellite data products. Fundamentals of measurement theory are taken through to implementation of practical ground based radiometers and their application to validate satellite data used to generate climate data records. This book presents practical solutions for those involved or contemplating the validation of optical climate measurements from satellite instruments.