All archeologists study past human cultures, with emphasis on the ways in which people and their societies have changed over time.  However, different archeologists have different interests in the past, ranging from earliest man to the relationship of modern communities to those known archaeologically.  Methodological approaches also vary, depending on what type of archaeological material is being studied, and more precisely, where it is being studied.  These sub-interests, or sub-specialities, require different types of knowledge and background, as explored below.

Cultural Resources Management (CRM)
Cultural resources management (CRM) is a specific branch of American archeology that functions specifically as part of the process by which the protection and management of cultural resources are ensured by law.  CRM is a vast and complex subject; therefore, an entire page has been dedicated to the topic.  To visit the CRM page, return to the Archeology page and select the CRM link at the bottom of the page.

Ethnoarcheology
Some archeologists practice ethnoarcheology, or the study of living cultures in search of analogous patterns applicable to the archaeological record.  Most commonly, ethnoarcheology involves the study of surviving hunter-gatherers, pastoralists, and nomads and the material remains and patterns of their daily lives in search of similarities in technology, mobility, and social-political organization applicable to attempts to reconstruct and explain the archaeological record.

Experimental Archeology
Experimental archeology relies on replication, experimentation, and ethnographic analogy to search for and test possible explanations for past behavior and change.

Garbology, or Garbage Archeology
Garbology is a modern sub-specialty of archeology that attempts to learn more about today’s society by studying what people throw away.  The University of Arizona Department of Anthropology pioneered garbology as a discipline more than 20 years ago, under the directorship of William Rathje.  Garbology research interests include modern diet, health, marketing, resource management, measuring the effectiveness of societial changes such as recycling and waste reduction over time, and demographic and social differentiation.

Historical Archeology
Historical archeology studies cultures with written history.  In the Old World, historical archeology covers a period of several thousand years; however, in the Americas, historical archeology is limited to the period after the arrival of Europeans.  Historical archeology contains several subfields, such as Classical archeology and Biblical archeology, not explored further in this section.

Prehistoric Archeology
Prehistoric archeology, with few exceptions, focuses on cultures lacking written language.  By necessity, therefore, most prehistoric archeology relies primarily on survey and excavation, or data recovery, to explore the past.

Underwater Archeology
Underwater archeology is a type of archeology based on location rather than temporal interest, as it focuses on archaeological investigations of material remains, such as shipwrecks and ancient campsites, preserved beneath the surface of oceans, lakes, rivers, and wetlands.  Underwater archeology requires very specific skills, such as deep-water diving, not typically associated with archaeological training.

Urban Archeology
Urban archeology is a branch of archeology specializing in large towns and cities with long stratigraphic Stratigraphy
The science of interpreting the layers present within an archaeological site. The basic principle of stratigraphy is the law of superposition, which states that lower deposits are older than higher deposits.
histories of occupation.  Some archeologists also use urban archeology to refer to any archeology conducted in an urban setting.