Social work is increasingly engaged in and with networks, making network orientation one of its core principles today. Its relevant networks exist at different levels and address various topics; they can open access to resources or pose challenges, and they can be very successful or just as easily fail. This textbook summarizes the central insights and discourses of network theory and also demonstrates how networks can be empirically captured and graphically represented. Additionally, a variety of case studies from network practice are outlined and discussed, which concretely and vividly address key themes of network orientation. The focus of the textbook is on work in institutional networks that is independent of individual cases.