In designing a phonological model we do not, as in the case of spoken language, have the advantage of being able to rely on a long tradition of proposals for feature sets and higher constructs. If linguistics is a young (and, some would say, immature) discipline, than sign linguistics has just been born. It essentially started in 1960 with the publication of Stokoe (1960), anticipated by earlier work that recognized the linguistic, communicative status of signing (for example Tervoort 1953). As might be expected from explorative proposals for feature sets, there has been a strong focus on the great richness of phonetic diversity of signs, and much less on phonological distinctiveness. As a consequence, most proposals for feature sets involve rather large sets of features, minutely encoding many phonetic details, and giving the impression that the feature structure of signed languages is much richer than that of spoken languages. Having said this, we do not wish to underestimate the enormous advances that have been made in the short period of 40 years by a relatively small group of linguists. In the early seventies we find foundational work in Klima and Bellugi (1973), reflecting the research of a group of influential researchers. In addition, several very detailed dissertations on the phonology of American Sign Language (ASL) appeared around that time, and throughout the eighties (for example Friedman 1976, Mandel 1981, Battison 1978, Sandler 1989; for overviews see Wilbur 1987). In this article, we will first discuss some of the earlier systems for the microstructure, ie the featural analysis of signs (section 2). Then, in section 3, we discuss some of the more recent developments which relate more to the macro-structure of signs. We present the results of this overview in terms of our own understanding of the macrostructure, ie the Leiden model. We make a number of comparative remarks about spoken and signed language in section 4. In section 5, we discuss a number of issues that arise in the study of sign phonology and phonetics. Section 6 contains our conclusions.