The 4th ISSNet Summer School was held at Dalhousie University in Halifax this year. Each year, ISSNet graduate students from across Canada get together for a week of workshops about computer security. It is an opportunity to network with other security researchers and to learn about aspects of security that they may not have previously studied. This year, they learnt about a variety of topics from operating systems, to Canadian privacy laws, data mining and visualization, and industry security administration and analysis.