In the present work polyacrylamide (PAM), copolymer nanogels, nanosize composites of AM with silica and functionalized composites of AM & 2-acrylamido-2-methyl-1-propanesulfonic acid with silica have been prepared by inverse microemulsion polymerization, in which water/toluene inverse emulsion was used to make the product a fine powder. These nanostructures have been characterized by DLS, FTIR, H-NMR, Elemental analysis, TGA, DSC, SEM & TEM to determine their size, polydispersity, presence of functional groups, polymer chain composition, thermal stability, morphology and shape. As easy availability of microemulsion literature is a constraint, this book emphasize on detail literature survey on microemulsion polymerization (mechanism); preparation, properties & applications of nanogels, nano size composites. This book being comprehensive in synthesis & characterization could be helpful to UG / PG / research scholars for understanding the peculiarity and easy steps for microemulsionpreparation, stabilization (with one / more surfactants / monomers) and in-situ polymerization.