Table of contents : 1 Introduction 2 Function spaces of Besov-Triebel-Lizorkin type 2.1 Definitions and fundamental properties 2.2 Embeddings 2.3 Some equivalent characterizations of Fsp,qand Bsp,q 2.4 Spaces on domains 2.5 Interpolation 2.6 Homogeneous spaces and a further supplement 3 Regular elliptic boundary value problems 3.1 Definitions and preliminaries 3.2 Estimates of integral operators 3.3 Estimates of the Poisson integral 3.4 A priori estimates 3.5 Regular elliptic boundary value problems 4 Pointwise multiplication 4.1 Introduction 4.2 The definition of the product 4.3 Necessary conditions for pointwise multiplication 4.4 Products of a function and a distribution 4.5 Products of functions and a distribution. The general case 4.6 The case of constant p 4.7 The extremal case p1 = p and p2 = . 4.8 Generalized Holder inequalities 4.9 The spaces Asp,q,unif and relations to M(Asp,q) 5 Nemytskij operators in spaces of Besov-Triebel-Lizorkin type 5.1 Introduction 5.2 Nemytskij operators in Lebesgue and Sobolev spaces 5.3 The Composition operator corresponding to a C.-function G in and Bsp