To investigate the composing processes of professional expository writers, interviews were conducted of six subjects who regularly produced expository prose under the pressure of a weekly or monthly deadline. Subjects included Noel Perrin, essayist, book critic, and Dartmouth College professor; Tom Wicker, political columnist for "The New York Times"; Walter Kerr, drama critic for "The New" magazine; Susan Nykamp, managing editor of "Photo Marketing"; and Neal Gabler, a cohost of the PBS program "Sneak Previews" and film critic for "Monthly Detroit." Each interview was recorded on cassette and conducted according to a previously prepared set of questions. In addition, the notes and drafts of at least two articles were collected. Four conclusions were drawn from the evidence and documentation: (1) writers continued to develop their abilities beyond the levels of mere proficiency or competence; (2) writers gained ability through immersion in contexts and increased familiarity with a habitual, predictable task environment; (3) writers' commitment to and proficiency with their subject depended upon the degree of their personal intellectual involvement or commitment to that subject; and (4) standards of quality in writing were flexible in the view of the writer according to exigencies and characteristics of the task environment. (HOD)