This book represents a compilation of papers presented at a symposium on the subject "Suspended Solids in Hater." held in Santa Barbara. California. U.S.A .* on March 20. 2] and 22, 1973. The symposium was sponsored by the Office of Naval Research and was designed to bring together a group that represented the domi nant cross section of international research in this area. The idea for the conference originated as ONR recognized a potentially interesting area that, to date. had not had the benefit of a co ordinating symposium and/or a book published on the specific sub ject. In addition to the formal presentation of papers - informal open discussions followed - the symposium included two stimulating workshops. An abundance of impromptu exchange filled unscheduled periods. Many of the contributors have incorporated in their pa pers the ideas and points raised in discussions following formal presentation and at other times. The reader thus actually profits from the various discussions throughout the meeting. The two half-day workshops were directed toward the subjects of sampling and concentrating suspended materials and in situ in strumentation. I have summarized the discussions from the two workshops for the reader and have correlated the material wherever possible in an introductory chapter. I have also included intro ductory material to acquaint the newcomer with the general field.