The Magellanic Clouds: their evolution, structure and composition

Recent data related to the history of the Magellanic Clouds as galaxies are described, and attempts to determine accurate distances to the Magellanic Clouds are discussed, with special attention given to the geometry of the Magellanic Clouds and different methods of distance determinations. Consideration is given to the various star generations present in the Clouds (i.e., the oldest generation, of greater than 10 Gyr; the intermediate-age generations, between 7 and 0.2 Gyr, and the youngest generation, the formation of which started only about 50 Myr ago) and to their occurrences in the LMC and SMC populations, as well as to the interstellar medium in the Magellanic Clouds. The structure of the Magellanic System, which comprises the Magellanic Clouds, the Intercloud Region, and the Magellanic Stream is described, with particualr consideration given to the complex structure of the LMC and SMC and the kinematics of their populations. (I.S.)