This monographic issue on alfalfa (alias lucerne) reflects the recent evolution of AEP (Association Européenne de Recherche sur les Protéagineux) into ILS (International Legume Society), i.e., a wider scientific community with a focus on both grain and forage legumes. This change recognizes the large affinities existing between these groups of crops for genetic and genomic characteristics (as confirmed by legume synteny studies and the key role played by Medicago truncatula as a model species) and in other respects, e.g.,the interactions of plants with nitrogen fixing bacteria, or the dynamics of associations of legume and nonlegume plants. There is also increasing opportunity for research projects devoted to improving simultaneously annual and perennial legumes, such as the FP7-ArimNet project REFORMA (Resilient, water- and energyefficient forage and feed crops for Mediterranean agricultural systems), which provided the context for the current editorial work. ILS initiatives, including this journal, will respond to the need for greater cultivation of legumes - of all kind.