  All three of these programmes generated new techniques for proof, constructions and classifications.  As we should expect, researchers have explored the range of application of each technique.  One result of this has been the emergence of several useful classes of first-order theories which relate to more than one of the three programmes.  For example a central tool of Shelah’s classification theory was his notion of forking, a far-reaching generalisation of earlier algebraic notions of dependence relation.  The class of simple theories is defined by the fact that forking has certain nice properties while the class of rosy theories is characterised by the existence of a good notion of independence coming from a further generalisation of forking called þ-forking; several natural examples of simple theories came to light in geometric model theory, and the complete theories of o-minimal structures are examples of rosy theories.  In parallel with these technical advances, first-order model theory continues to grow more closely involved with problems in number theory, functional analysis and other branches of pure and, and even applied, mathematics.