It is unclear why or when the phrase comprised of crept into the language and began to be used interchangeably with composed of, as in "the company is comprised of four divisions." Although the use of comprised of is increasingly accepted, careful writers and speakers insist on holding to the traditional meaning of to comprise, which is to include or contain. I recommend that you do likewise. It makes no more sense to say "comprised of" than to say "included of." Think of it this way: The whole comprises (includes) the parts; the parts compose (constitute) the whole. Thus, "The company is composed of four divisions" or "The company comprises four divisions."