Information sharing is a crucial step to acquiring a thorough understanding of large-scale cyber-attack situations, and is therefore seen as one of the key concepts to protect future networks. To this end, nation-states together with standardization bodies, large industry stakeholders, academics and regulatory entities have created a plethora of literature on how cyber security information sharing across organizations and with national stakeholders can be achieved. Shared information, commonly referred to as threat intelligence, should comprise timely early warnings, details on threat actors, recently exploited vulnerabilities, new forms of attack techniques, and courses of action on how to deal with certain situations--just to name a few. Sharing this information, however, is a highly non-trivial task. A wide variety of implications, regarding data privacy, economics, regulatory frameworks, organizational aspects and trust issues need to be considered. Collaborative Cyber Threat Intelligence surveys and presents existing works, and proposes and discusses new approaches and methodologies at the forefront of research and development--back cover.