Presented at the European Molecular Biology Organization workshop, Seillac, France, 15-19 May 2006, organized by S. West, A. Nicolas and M. Foiani.-- Final full-text version of the paper available at: http://dx.doi.org/10.1038/sj.embor.7400872The accurate repair of DNA double-strand breaks (DSBs) is crucial for the maintenance of genome stability and the prevention of tumours. Homologous recombination (HR) is a complex process used by cells to repair DSBs that arise spontaneously during DNA replication or after exposure to DNA-damaging agents. HR is also fundamental for DSB-initiated DNA transactions, which occur during meiosis, V(D)J recombination and mating-type switching. During the past decade, many HR components have been identified using genetic and biochemical approaches (Jasin, 2002; Keeney, 2001; Lisby & Rothstein, 2004, 2005; Liu & West, 2004; West, 2003); the main challenge now is to define how known HR components function at the molecular level. The first workshop on recombination was held in 1968 and was a highly stimulating meeting that focused on how DNA could be manipulated to achieve recombination. Since then, the field has expanded considerably. This was reflected in the most recent meeting, which brought together scientists studying many areas of DNA metabolism that either use or have a direct effect on HR.Peer reviewed