These thirteen articles, and the full discussion that follows each, derive from papers given by specialists from the US, Australia, Singapore, and Western Europe at an April 2000 symposium in London. The text includes discussion of cell size control, asymmetric cell division, the specification of cell fate decisions and cell death. Individual papers discuss the pattern and growth-linked cell cycles in Drosophila development, the regulation of the embryonic cell proliferation by Drosophila cyclin D and cyclin E complexes, cell cycle regulation in early mouse embryos, regulation of Drosophila imaginal disc growth by the insulin/IGF signalling pathway, and control of cell fate in plant meristems.