Cancer genomes accumulate a large number of somatic mutations resulting from imperfections of DNA processing, naturally occurring DNA damage, replication errors, disregulation of DNA repair mechanisms, and carcinogenic exposures. These mutagenic processes often produce characteristic mutational patterns called mutational signatures. The decomposition of a cancer genome’s mutation catalog into mutations consistent with such signatures can provide valuable information about cancer etiology. I will present several computational approaches for studying mutagenic processes and their interplay through the lens of mutational signatures.