Ferrofluids are smart materials possessing high controllability over its sensing and actuations behaviour which makes them suitable for contemporary technology. This book provides a comprehensive and accessible account of the material aspects of ferrofluids and its composites. It covers all the aspects of ferrofluids from physical to colloid stability factors, optical to thermal behaviour and rheological properties. An account of ferrofluid applications such as fine polishing, energy conversion, biomedical and further scope is presented. This book is indispensable for researchers, academicians and technologists working on magnetic nanosuspensions.