Book excerpt: Much of the biology of oxidative stress and oxidative signalling centres on the generation and handling of hydrogen peroxide. The overall aim for this book would be to provide an insightful and useful forum to assist with the understanding of the relevance of hydrogen peroxide generation and how this is managed in human biology. The target audience would be those who currently have an interest in the generation of ROS, but who do not have expertise in chemistry, as well as those experts in the chemistry of oxidative stress, but without detailed understanding of the biologically relevant setting. We would aim to bridge the gap in understanding between chemistry and biology.