Protides of the Biological Fluids contains the proceedings of the 26th Colloquium in 1978. Two topics are highlighted, the first one being the immune complexes and the second one being the cytoskeletal proteins. This book is organized into three sections, namely, Immune Complexes, Cytoskeletal Proteins, and Techniques. The Immune Complexes section states the biochemical problems and answers some intriguing clinical problems in this field. This section details the theory of the antigen/antibody reaction, the isolation of complexes, and the nature of the antigen. The Cytoskeletal Proteins section discusses the theoretical aspect of cell structure. The last section describes the assay methods and individual protein assays.