This newly updated Soil Survey Manual provides the major principles and practices needed for making and using soil surveys and for assembling and using related data. Although written by a US governmental agency, it contains information relevant to all issues related to soil, regardless of locale.
The complete Soil Survey Manual and / or individual chapters are available as a pdf download at the following link:
https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/soils/ref/?cid=nrcs142p2_054262