Two types of knowledge are essential in method engineering: knowledge of information system development and knowledge of method development. In this chapter we focus on the latter, method engineering and especially on the methods, modeling languages and tools of method engineering.

The chapter is organized as follows. In Section 3.1 we define ME and in Section 3.2 we analyze different ME approaches based on their ME process, the types of method knowledge they consider, and the factors or criteria driving ME. These must be described to understand the principles of incremental ME (cf. Chapter 5) necessary to extend the current ME principles. Moreover, tool adaptation as a mechanism to obtain method-tool companionship leads us to explain the role of CAME, metaCASE and CASE tools. In short, we shall focus on creating and maintaining knowledge about modeling techniques in ISD tools. Accordingly, in Section 3.3 we describe metamodeling languages by focusing on how to specify the conceptual structures of modeling techniques. The presentation of metamodeling languages is accompanied with a metamodeling example. This presentation is needed to understand the constructs of metamodeling languages and the evaluation of the metamodeling languages carried out in Chapter 4.