Fixers, facilitators, go-betweens. Police liaison officers across the globe are often associated with a wide but rather ominous range of roles and tasks. In reality, liaison officers are formal representatives of their respective governments in charge of maintaining cross-country relationships with relevant law enforcement agencies. Though associated with friendly atmospheres and exotic destinations, these networked professional relationships are generally sensitive and rather demanding in nature. Over the past forty years liaison officers have increasingly played a pivotal role in the field of police cooperation, first recognized in 1993 by Nadelmann in his seminal work `Cops Across Borders. In spite of their growing role in police cooperation, almost no empirical research has been done since Nadelmann and also Bigo turned the lights on them. Meanwhile police agencies, certainly in Europe, have almost without exception adopted the model of liaison officers as an effective tool for international police cooperation. But how much do we actually know about liaison officers, their work, their dilemmas, and the politics surrounding their deployment? How do policies and budget developments affect liaison officers schemes? What can be said about their preparation and professionalization? This book presents rich and illustrative empirical material on the use of liaison offices in police cooperation. The authors, both eminent academics and seasoned practitioners (and in some cases from a dual academic-practitioner background), present their findings from a wide range of geographical and functional viewpoints. Students and law enforcement professionals are made familiar with the blue web of policing across the world. This book offers them a considerable variety of perspectives, ranging from academic to professional, from institutional to informal, and from sociological to psychological. Together the detailed accounts form a inspiring collection on contemporary practices of liaison officers that not only includes original empirical research, but also forms a work of reference as well as a unique textbook for students of international security and policing.