This is page i Printer: Opaque this Logarithmic Combinatorial Structures: a Probabilistic Approach Richard Arratia, 1 A. D. Barbour 2 and Simon Tavar´ e DRAFT. November 26, 2002 1 RAA and ST: Department of Mathematics, University of Southern California, 1042 W. 36th Place, DRB 155, Los Angeles, CA 90089–1113, USA. 2 ADB: Abteilung f¨ ur Angewandte Mathematik, Universit¨ at Z¨ urich, Winterthur- erstrasse 190, CH–8057 Z¨ urich, Switzerland