This publication, Keys to Soil Taxonomy, Twelfth Edition, 2014, coincides with the 20th World Congress of Soil Science, to be held on Jeju Island, Korea in June 2014. The Keys to Soil Taxonomy serves two purposes. It provides the taxonomic keys necessary for the classification of soils in a form that can be used easily in the field. It also acquaints users of soil taxonomy with recent changes in the classification system. The twelfth edition of the Keys to Soil Taxonomy incorporates all changes approved since the publication in 1999 of the second edition of Soil Taxonomy: A Basic System of Soil Classification for Making and Interpreting Soil Surveys. The authors of the Keys to Soil Taxonomy are identified as the ?Soil Survey Staff.? This term is meant to include all of the soil classifiers in the National Cooperative Soil Survey program and in the international community who have made significant contributions to the improvement of the taxonomic system.