The sixteen papers in this Special Issue cover various aspects of cyber security and will appeal to those involved in cyber security research, practitioners, students contemplating a career in cyber security, and people interested in the topic but who have limited knowledge of the challenges that exist and the possible solutions that can help solve recurring cyber security problems. The emphasis and focus of the papers is threat detection and ways in which to make an organization resilient and able to withstand and counteract cyber attacks. The approaches referred to herein can help deepen an organization's cyber security defence capability, but there are also topics of interest for policy-makers and those involved with governance and compliance. The papers included in this Special Issue involve different methodological approaches and offer practical insights that will help advance the body of knowledge on cyber security.