In the preparation of this descriptive manual of the rust fungi of the grasses of the world the principal goal was to produce a system by which these important pathogens might be recognized on the basis of their morophology, without dependence on the identity of the host plant. This is an Utopian goal and, being Utopian, has doubtless not been attained. But it is better to have tried and partially failed than not to have tried at all. The first attempt...