Nature Reviews Chemistry is an online-only journal for the weekly publication of Reviews, Perspectives and Comments in all disciplines within chemistry. Our Reviews aim to be balanced and objective analyses of the selected topic – with descriptions of relevant scientific literature and discussions that are easy to grasp for recent graduates in any chemistry-related discipline, as well as informing principal investigators and industry-based research scientists of the latest advances. Reviews should provide the authors' insight into future directions and their opinion of the major challenges faced by researchers in the field. Perspectives – as the name suggests – take a look at a topic from a slightly different angle. They may offer more personal viewpoints, explain the historical background to a topic, or discuss some of the social, ethical or environmental factors related to chemistry research in academia and industry.