Observation is one of the most important research methods in social sciences and at the same time one of the most diverse. The term includes several types, techniques and approaches, which may be difficult to compare in terms of enactment and anticipated results; the choice must be adapted to the research problem and the scientific context. As a matter of fact, observation may be regarded as the basis of everyday social life for most people; we are diligent observers of behaviors and of the material surroundings. We watch, evaluate, draw conclusions and make comments on interactions and relations. However, observation raised to the rank of a scientific method should be carried out systematically, purposefully and on scientific grounds - even if curiosity and fascination may still be its very important components.In this chapter, we discuss the main characteristics of three types of observation, that can be used in different ways and to some degree even combined. In participant observation, the researcher strives towards an "immersion" in a specific culture, preferably for a longer period of time, in order to acquire an insider understanding of this culture either as a (marginal) member or as a visitor. In non-participant observation, the researcher tries to understand the world, relationships and interactions in a new way, without prevalent categorizations and evaluations. In indirect observation, the researcher relies on observations done by others (e.g. other researchers), on various types of documentation, recordings or on auto-observation.In the first part of this chapter, we discuss common features of different observation techniques and some essential elements in the design of a study based on observation methods. We also consider some possible roles an observer may take and be ascribed, and how to document the observations in a form of notes. In the second part, we discuss different approaches to direct and indirect observation.