This volume, Biology of Poxviruses, marks our debut as editors of this well known series. We plan to continue the tradition of providing a forum for exten sive, critical reviews of individual virus groups, as exemplified by the present volume. But the pace of discovery is accelerating so rapidly that we feel the need to offer an additional format: volumes that contain collections of shorter, topical reviews on a group of related subjects. Such collections might cut across con ventional boundaries between virus groups, dealing, as an example, with a partic ular aspect of virus-cell interaction. Admittedly, this new format stretches the term monograph beyond the accepted definition, but we believe that we should pay that price to maintain the usefulness of the series as a medium of scientific communication. Whenever possible, we will enlist the aid of deputy editors to bring such col lections to fruition. As in the past, the editors and the publisher will welcome suggestions for topics and contributions.