The book "Information Systems Security and Privacy" presents the revised selected contributions from the Third International Conference on Information Systems Security and Privacy (ICISSP 2017), which took place in February 2017 in Porto, Portugal. It includes 13 full papers that were carefully selected from a total of 100 submitted contributions. The topics covered are diverse, ranging from vulnerability analysis and countermeasures to the discovery of attack patterns and intrusion detection, as well as malware classification and detection. Additionally, it addresses applications of cryptography, data protection and anonymization, security policy analysis, enhanced access control, and the socio-technical aspects of security. This academic book thus provides a comprehensive overview of current challenges and solutions in the field of information security and data protection.