The marine phytoplankton, the microalgae make up a quarter of all vegetation on the planet and could be the oldest known basic food source in the seas and oceans. The marine zooplankton, on the other hand are the initial prey items for almost all fish larvae. Most of the marine fishes and associated fisheries rely largely on the density and distribution of zooplankton. This comprehensive publication deals with all methods of studying marine phytoplankton and zooplankton including their identification. It is hoped that this publication, first of its kind would be of great use for the students and researchers of disciplines such as Fisheries Science, Marine Biology, Aquatic Biology and Fisheries and Zoology besides serving as a standard reference for other Biology-related faculties.