'Geological Survey Research 1966' is the seventh annual review of the econamic and scientific work of the U.S. Geological Survey. As in previous years the purpose of the volume is to make available promptly to the public the highlights of Survey investigations. This year the volume consists of 4 chapters (A through D) of Professional Paper 550. Chapter A contains a summary of significant results, and the remaining chapters are made up of collections of short technical papers. Many of the results summarized in chapter A are discussed in greater detail in the short papers or in reports listed in 'Publications in Fiscal Year 1966,' beginning on page A265. The tables of contents for chapters B through D are listed on pages A259-A264. Numerous Federal, State, county, and municipal agencies listed on pages A211-A215 cooperated financially with the Geological Survey during fiscal 1966 and have contributed significantly to the results reported here. They are identified where appropriate in the short technical papers that have appeared in Geological Survey Research and in papers published cooperatively, but generally are not identified in the brief statements in chapter A. Many individuals on the staff of the Geological Survey have contributed to 'Geological Survey Research 1966.' Reference is made to only a few. Frank W. Trainer, Water Resources Division, was responsible for organizing and assembling chapter A and for critical review of papers in chapters B-D, assisted by Louis Pavlides, Geologic Division. Marston S. Chase, Publications Division, was in charge of production aspects of the series, assisted by Jesse R. Upperco in technical editing, and William H. Elliott and James R. Hamilton in planning and preparing illustrations. The volume for next year, 'Geological Survey Research 1967,' will be published as chapters af Professional Paper 5715. Previous volumes are listed below, with their series designations. Gealagical Survey Research 1960-Prof. Paper 400 Gealagical Survey Research 1961-Prof. Paper 424 Gealagical Survey Research 1962-Prof. Paper 450 Gealagical Survey Research 1963-Prof. Paper 475 Gealagical Survey Research 1964-Prof. Paper 501 Gealagical Survey Research 1965-Prof. Paper 525