Educational assessment is discussed, describing three images of instructional design that can be used to construct classroom learning environments, and focusing on the nature and uses of portfolios and authentic assessment. The following three designs for schooling are considered: (1) discipline-centered schooling, the most familiar vision of teaching; (2) empirical-naturalistic schooling, in which students assist students in shaping their uncertainties into problems that can lead to significant and integrated learning; and (3) Great Works schooling, in which students develop interpretive powers through shared inquiry into works of literature or art. Portfolio construction and assessment are reviewed and discussed in the context of authentic assessment. A continuum of authentic assessment is proposed, and problems in its development are explored. Portfolio assessment can be a means toward a more authentic evaluation of learning. Use of portfolios can make teaching a far more participative process. (Contains 10 references.) (SLD)