No single prescription can tell us how to deal with problematic fossil taxa. The fact that there is very little evidence is demonstrated in the highly divergent interpretations of a number of problematica. The editors of this volume provide the reader with updated ideas on most of the major problematic fossil taxa, showing that a sweeping change in the paradigm of study is under way. The contributors focus particularly on Early Paleozoic organisms, although Precambrian biota are also discussed. Each fossil group is discussed by an international specialist on the group, and the book is comprehensively illustrated with fossil photographs and diagrams.