Cells may be seen as superb 'factories' in so far as they take in one set of chemicals (nutrients) and convert them into new products. Each cell taking in its own set of chemicals and making its own collection of products. Describing the structuralorganisation of cells in both unicellular and multicellular organisms this text considers the organisation and management which lead to these 'factories' operating in a coordinated and functional manner. Reproduction, the one feature special to cellactivities is addressed in detail.