A collection of 15 articles that highlight research carried out using the international Collaborative Cross project has been published in Genetics and G3: Genes, Genomes, Genetics. In the past decade, the Collaborative Cross project has developed recombinant inbred lines of mice, each containing a different genomic contribution from eight founder strains. Some papers cover the mapping methodology, and others describe the development and successful application of the Collaborative Cross — and of a related 'Diversity Outbred' resource — to studying the effect of sequence variation on many mouse traits. The traits range from blood pressure or glucose levels to the adverse response to drugs.