Although adenoviruses have been established for quite some time as one of the most pliable tools to study the molecular biology of mammalian cells, rapid progress continues to be made with this virus system. The adenoviral genome introduced into the nucleus of cells as a Trojan Horse, as it were, is now facili- tating investigators to uncover details of cellular mechanisms. In this volume twelve chapters have been collected that summarize important current research on different mechanisms in adenovirus- infected and -transformed cells. It has become increasingly apparent that some of these mechanisms do not only pertain to highly specialized strategies of the viral genome and its expres- sion or replication, but may simultaneously shed light on events indigenous to the cell. "Adenovirus DNA: The Viral Genome and its Expression" high- lights the first publication of the entire annotated sequence of 35. 937 nucleotide pairs of adenovirus type 2 DNA by the Cold Spring Harbor and Uppsala groups (chapter 1). Goran Akusjarvi, Ulf Pettersson (Uppsala University) and Rich Roberts (Cold Spring Harbor) present a survey on the structure and function of the adenovirus-2 genome (chapter 2).A considerable amount of in- formation has been collected on the biochemical mechanisms in- vol ved in adenov irus DNA repl ication in human cells. Al though highly specialized in the way of initiating DNA replication, adenov irus DNA repl ication represents probably one of the best studied systems in work on eukaryotic DNA replication.