Summary: In the literature on encompassing (see, e.g., [\textit{G. E. Mizon} and \textit{J.-F. Richard}, Econometrica 54, 657--678 (1986; Zbl 0625.62105); \textit{D. F. Hendry} and \textit{J. F. Richard}, ``Recent developments in the theory of encompassing'', in: Contributions to operation research and econometrics. The Twentieth Anniversary of CORE. Cambridge: MIT Press. 939--400 (1990); \textit{J. P. Florens} et al., Parsimonious encompassing: an application to non-nested hypotheses and Hausman specification tests. Durham, NC: Duke University (1987)]) there is a basic contradiction: on the one hand it is said that it is not possible to assume that the true distribution belongs to one of two competing model \(M _{1}\) and \(M _{2}\), but, on the other hand, this assumption is made in the study of encompassing tests. In this paper we first propose a formal definition of encompassing, we then briefly examine the properties of this notion and we propose encompassing tests which do not assume that the true distribution belongs to \(M _{1}\) or \(M _{2}\); these tests are based on simulations. Finally, generalizing an idea used in the definition of an encompassing test (the GET test) we propose a new kind of inference, called indirect inference, which allows for estimation and test procedures when the model is too complicated to be treated by usual methods (for instance maximum likelihood methods); the only assumption made on the model is that it can be simulated, which seems to be a minimal requirement. This new class of inference methods can be used in a large number of domains and some examples are given. The present paper is based on [the first author et al., Econometrica 52, 681--700 (1984; Zbl 0575.62031); ``Indirect inference'', J. Appl. Econom. 8, No. S1, S85--S118 (1993; \url{doi:10.1002/jae.3950080507})], respectively GM and GMR hereafter.