The Manual is intended primarily for use by soil scientists engaged in the work of making soil surveys. It is an especially important reference for soil scientists early in their careers as they learn the many complex aspects of making a soil survey. It is also an important reference for experienced soil surveyors who want to review the details regarding many of the standards used in soil survey. For example, chapter 3, "Examination and Description of Soil Profiles," contains the accepted terms and definitions for specific soil properties that are used when describing soil profiles in the field. It also contains extensive information describing each soil property and the proper procedures for observing or measuring it in the field. The Manual is therefore an important companion to other soil survey references, such as the National Soil Survey Handbook (USDA-NRCS, 2016), the Field Book for Describing and Sampling Soils (Schoeneberger and Wysocki, 2012), and the Keys to Soil Taxonomy (Soil Survey Staff, 2014). Although the Manual is oriented to the needs of those actively engaged in preparing soil surveys, workers and students who have limited soil science experience or are less familiar with the soil survey process can also use the information. Teachers, researchers, and students of soil science and related disciplines, especially those interested in pedology, soil morphology, soil geography, ecology, geomorphology, and the science underlying soil survey, will find this manual useful. Resource specialists, such as wetland scientists, foresters, and agronomists, and others who use soil surveys in their work, can refer to the Manual to better understand how soil surveys are made and how to interpret the technical information they provide. Parts of the Manual, especially those concerning the description of soils in the field and the soil properties considered when predicting soil behavior under a specific use, have been adopted by private-sector soil scientists as standards. The Soil Survey Manual has proven to be an important source of information for government agencies, nongovernmental organizations, and private-sector resource specialists in other countries involved in soil survey projects. Because the Manual describes all facets of the soil survey process, it is an important guide for developing proposals to conduct soil surveys and to create detailed plans for projects in other parts of the world. The Manual serves as the guiding document for activities of the National Cooperative Soil Survey (NCSS), a cooperative undertaking led by the United States Department of Agriculture. The NCSS includes other Federal and State agencies, universities, non-governmental organizations, and private-sector soil scientists interested in making soil surveys and/or interpreting and using soil survey information. The original Federal authority for the Soil Survey of the United States is contained in the record of the 53rd Congress, Chapter 169, Agricultural Appropriations Act of 1896. The authority was elaborated in Public Law 74-46, the Soil Conservation Act of April 27, 1936, and again in Public Law 89-560, Soil Surveys for Resource Planning and Development, September 7, 1966. The Manual is the primary reference on the principles and technical details used by the local, State, and Federal contributors to soil surveys authorized under these acts.