It is often claimed that we live in an expert society, a society where more and more individuals take expert roles in increasingly narrow fields. In contrast to more traditional experts most of these new experts lack generally accepted mechanisms for the certification and legitimation of their expertise. This book focuses on these new as well as established experts and the efforts undertaken to secure and legitimate their expertise. We view these efforts as organizing attempts and study them on four different levels the society, the market, the organization and the individual.