[en] The stellar content and history of star formation of a number of Irregular and other late-type galaxies were analyzed by means of 10-color photometry of the galaxies and a comparison of their colors to the calculated colors of a set of three-parameter models. The galaxy models are assumed to be composed of various amounts of ''clusters'' from 10⁶ to 10¹⁰ years old, the colors of which were calculated from stellar-evolutionary tracks and observations of 102 stars of all spectral types. The colors of the model clusters were checked by comparison to the colors of 46 clusters in the Magellanic Clouds