This book seeks to draw a comprehensive picture of influencer collaborations from a strategic communication perspective. The contributors tackle strategic influencer communication from multidisciplinary perspectives, from varying actor foci, and from different methodological frameworks and methods. Influencers cross traditional boundaries in many ways and oscillate between intimacy and publicity, authenticity and commercialization, ingratiation and critical distance. From a strategic communication perspective, this variability makes influencers hard to capture: organizations can cooperate with influencers to achieve both marketing and PR objectives. Influencers can act as cooperation partners, integrating commercial content into organic narratives, or as independent critics. Influencers also combine different roles that have traditionally been occupied by separate actors such as intermediary, content distributor, creative content producer, community manager, testimonial, strategic counsellor, and event host. The combination of these roles in just one actor opens new opportunities for strategic communication and can produce appreciated synergy effects. It is therefore hardly surprising that influencer collaborations have become a firmly established instrument in the toolbox of strategic communicators. The chapters in this book were originally published in the International Journal of Advertising and the International Journal of Strategic Communication.