Security intelligence continues to be of central importance in a world characterized by a wide range of risks and high levels of uncertainty: states, organizations, groups and individuals all seek timely and actionable information in order to increase their sense of security. But what exactly is intelligence and how can we ensure that it is not abused? While this third edition is substantially revised and updated, we have retained the essential structure of the first two editions in analysing how and why intelligence processes work as they do in a variety of state and non-state settings.

The continuing significance of intelligence and the increasing study of it taking place in many universities could well have encouraged a longer book, but we decided to concentrate on the essentials, from which readers may embark on their own further research. In updating examples, we have provided more from Europe, since the literature on this area is still far less extensive than it is on the US. The other main changes we have made reflect either significant developments, such as the role of intelligence in the cyber realm, both in terms of defence and offence, the implications and consequences of the leaking of information from the US National Security Agency by Edward Snowden, or new departures in Intelligence Studies. Different aspects of recent terrorist attacks in Belgium, France and Germany are discussed in several chapters, especially in relation to debates about sharing, ‘failure’ and oversight.

Chapter 1 surveys the evolution of intelligence and considers how we define the term. One of the main developments discussed here is an alternative to the outdated concept of an intelligence ‘cycle’ that has provided the bedrock for studying intelligence since serious attempts were first undertaken in the mid-twentieth century. The structure of Chapter 2 remains essentially intact, as we develop a conceptual framework for the study of intelligence. Chapter 3 compares the major features of intelligence in democratic, authoritarian and hybrid regimes and provides an updated review of some of the main intelligence organizations both inside and outside the state. The increasing interdependence between these is shown to be highly significant.

Chapter 4 examines the main methods of information gathering or collection. Increasingly, agencies access the electronic information trail left by individuals going about their daily lives; the publication since 2013 of the ‘Snowden files’ has not just increased greatly what is known about the work of the NSA and GCHQ and their interception of Internet communications and social media, but has also given rise to much debate and changes to legislation in several countries. Chapter 5 deals with the analysis of information, development of ‘intelligence’ and its dissemination. We examine the continuing increase in the use of Web 2.0 technologies in order to enhance information sharing and analysis, while noting the continuing organizational problems that can prevent effective sharing. Chapter 6 focuses on what we term the ‘intensification of surveillance’, where surveillance becomes ‘action’. It considers a range of examples, including the use of unmanned aerial vehicles (UAVs, or drones), not just for purposes of monitoring or watching, but also for killing those targeted, and offensive cyber strategies and the problem of definitive attribution in this sphere of activity.

The intelligence ‘failure’ that was the misapprehension of weapons of mass destruction in Iraq in 2002–3 remains a seminal issue, and its coverage is updated in Chapter 7 in the context of the long-awaited publication of the Chilcot Report in the UK. There is also a more general consideration of how ‘failure’ is perceived and analysed as well as an examination of its causes, including whether the traditional model relating to ‘strategic’ intelligence is equally applicable to more ‘tactical’ questions of counterterrorism. The core of Chapter 8 remains the issue of democratic control: the challenge facing all of us is to maintain some semblance of democratic control over enhanced intelligence networks of state and non-state entities. Examples of the legal changes made post-Snowden in Germany and the UK are discussed, as is the continuing problem of apparently endless delays when inquiries are set up to examine intelligence abuses. As before, Chapter 9 seeks to draw our conclusions and identify major current challenges to intelligence, including the potential for its use as a tool for ‘human’, and not just ‘national’, security.

Our continuing involvement in seminars, workshops and conferences over the past few years, in which we have discussed many of the themes developed here, leaves us further indebted to colleagues. We have not attempted to list them all here, but we are confident they know who they are! Thank you. We are also grateful to Louise Knight, Nekane Tanake Galdos, Rachel Moore and Sarah Dancy at Polity for their encouragement and assistance in preparing this new edition. We remain much in debt to Pen Gill and Di Phythian for their continuing support. Finally, we acknowledge that any errors are entirely our responsibility.