Robert Engelman analyzes population prospects while challenging public perceptions of population projections. These projections are valuable tools for considering the human prospect. They are, however, misunderstood as reliable guides to the future of human numbers, and this misunderstanding has potentially hazardous consequences. In particular, the apparent mathematical precision of projections encourages the misconception that there is nothing anyone can do about population growth, when there is very much we can and should do. The usefulness of projections could be enhanced by much more open discussion of the assumptions that underlie them, and an occasional challenge of some of those assumptions.