This chapter examines what sources and types of knowledge managers access and use in practice to cope with the many challenges, what possibilities and limitations this suggests for applying more general management knowledge to a healthcare setting and what, in turn, this means for understanding healthcare managers' professional basis and identity. It describes the orientations of managers in the authors' study towards different forms and sources of management knowledge and how these were interrelated in and through their management practice. The chapter explores how their approach to management was influenced by their particular professional background; how particular codified forms of knowledge may have been mobilized and utilized by managers; how organizational reporting requirements influenced the managerial knowledge base required; and how important personal experience and experiential learning was to their management practice. Managers only very rarely made explicit reference to established and codified systems of management knowledge which were consciously drawn upon and applied to their work.