This volwne consists ofpapers written by evolutionary, molecular and organismal biologists, geneticists, ecologists, behavioural ecologists, morphologists, mathematicians, theoreticians and experimentalists, in honour of Professor Eviatar (Eibi) Nevo on the occasion ofhis seventieth birthday. The contributors are only a small subset ofEibi's many friends, collaborators and students (not that one can distinguish these categories among Eibi's colleagues). His widespread influence and activity, both in Ismel and more genemlly, as a leading evolutionary biologist is indicated by his many co-authors on books and papers, and byhis many students integmted in teaching and research. Sensible publishers, and indeed readers, reflexively flinch from Festschrifts, which too often are well-intentioned but inchoate collections of papers (frequently recycled). This particular collection, however, is unified by the way the editors have built on Eibi's own work, to provide a connective narrative and synthesis, much ofwhich is new material. The unifYing thread is evolutionary theory. As a result of recent advances at the interface between molecular and organismal biology, evolutionary theory is currently undergoing one of its most dynamic and dramatic developments, unravelling the origins, structure and evolution ofliving organisms. Over the past four decades, studies ofthe causes and consequences of biological diversity at every level - genes, genomes, populations, species, ecosystems, - have revolutionised evolutionary biology. New perspectives in ecological dynamics and in molecular biology and in diversity, along with complete sequencing ofthe first prokaryote and eukaryote genomes, highlight the evolutionary origins and relationships which underlie the unity and diversityoflife onour small planet.