The book addresses the concept of knowledge in a work and organizational context, professional or knowledge work, and knowledge-intensive firms. It provides a critical, moderate social constructivist understanding of these themes and the current interest in knowledge management, organization and the "knowledge economy". Professional service as well as science and high-tech work and firms are treated, reporting case studies of IT and management consultancy firms, advertising agencies and life science based companies. The concepts of knowledge and knowledge management are discussed and dominant functionalist thinking debunked. The ambiguity of knowledge in the input, process and output of professional work is emphasized. It is suggested that we should be careful in assuming too much about the nature, role and effects of "knowledge" in business life and instead take the constructed nature of knowledge seriously and scrutinize knowledge claims. Knowledge talk and claims may frequently be key elements in marketing and identity work as much as they inform us about key activities of professionals and knowledge-intensive firms. The book covers a fairly broad set of management, organization and working life aspects are addressed, including HRM themes and different forms of control including client control and regulation of identity. From a perspective emphasizing the ambiguity of social and business life, rhetoric, symbolism, image, politics of knowledge claims, identity and identity work are viewed as crucial for the understanding and management of professional/knowledge work and organizations. The book is provocative and challenges key assumptions in dominant knowledge and organization thinking, suggesting a novel theoretical approach. The book is intended for third year level undergraduates upwards, and aims to say things also of relevance for scholars. It mixes textbook and research ambitions. As a (moderately) constructivist text with a relatively broad focus, the book may have some potential as a text complementing more conventional textbooks also in general organization and management courses.