This paper is concerned with developing Joan Bybee's proposals regarding the nature of grammatical meaning and synthesizing them with Paul Hopper's concept of grammar as emergent. The basic question is this: How much of grammar may be modeled in terms of grammaticalization? In contradistinction to Heine, Claudi & Hünnemeyer (1991), who propose a fairly broad and unconstrained framework for grammaticalization, we try to present a fairly specific and constrained theory of grammaticalization in order to get a more precise idea of the potential and the problems of this approach. Thus, while Heine et al. (1991:25) expand – without discussion – the traditional notion of grammaticalization to the clause level, and even include non-segmental structure (such as word order), we will here adhere to a strictly 'element-bound' view of grammaticalization: where no grammaticalized element exists, there is no grammaticalization. Despite this fairly restricted concept of grammaticalization, we will attempt to corroborate the claim that essential aspects of grammar may be understood and modeled in terms of grammaticalization. The approach is essentially theoretical (practical applications will, hopefully, follow soon) and many issues are just mentioned and not discussed in detail. The paper presupposes a familiarity with the basic facts of grammaticalization and it does not present any new facts.