The special feature of this issue of Humanitarian Exchange focuses on the response to the January 2010 earthquake in Haiti. The earthquake killed more than 220,000 people and directly or indirectly affected almost one-third of the Haitian population. Although much of the early media coverage emphasised the tardiness and inefficiency of the humanitarian response, subsequent reviews have recognised the complex operating environment and the extensive challenges involved. That does not, however, mean that mistakes were not made. As Sir John Holmes reminds us in his overview article, we must not only note our mistakes but 'act on the lessons we have learned with speed and determination, striving constantly to improve our response'.