The term geostatistics, likely first used in the 1950s/1960s as "géostatistique" in French, encompasses all statistical theories, estimation, and inference methods applied in the geosciences. An important subfield is the theory of stochastic processes and its application to functions and fields that fluctuate randomly in space and time. There are excellent mathematical works on stochastic processes, but they can primarily be utilized by theorists rather than practitioners. Technically oriented books, such as those on control engineering and systems theory, primarily address one-dimensional stochastic processes; they are more accessible to practitioners, provided they can handle the specific technical terminology. Although the geosciences themselves have made significant contributions to the development of the theory of stochastic processes.