Thanks to the diversity of the B cell repertoire the immune system can adapt to nearly any pathogen it encounters. This ability protects from recurrent infections, helps guard against rapidly mutating pathogens and is the basis for vaccines. Despite its importance the nature of this diversity and how it is generated remains unknown. The evolution of multivariate receptor repertoires and the selection of specific subsets, during the lifetime of the organism, cannot be understood at the level of a single cell. We study this system by developing tools that allow us to analyze and visualize nucleotide and protein relationships at the level of the whole repertoire of cells. Using these tools we are starting to identify how the B cell repertoire retains homeostasis while maintaining focus on specific epitopes.