Biological and medical research relies upon an integrated understanding of the molecules within cells and of the interactions between cells. This has imposed great demands on investigators. Being an expert in a relatively narrow area is no longer sufficient as many studies now require the use of a wide range of techniques to provide the necessary integration. A lack of familiarity with the experimental possibilities can make such diversification difficult to achieve. This two volume set of Essential Cell Biology is designed to help researchers overcome these problems. It has not been possible to include all of the techniques available in cell biology so the challenge was to identify those that might be most relevant to researchers who are new to this topic. We have tried to cover both traditional and more recent approaches. The theory and basic principles of each technique are described, together with detailed protocols and advice for trouble shooting. Directions to more specialised techniques are also included. We hope the result inspires readers to experience the challenges and rewards of cell biology research for themselves and to contribute to the ongoing task of understanding the life of the cell. Essential Cell Biology volume 2 concentrates on understanding how the cell functions whilst Volume 1 focuses on techniques for studying cell structure. Volume 2 details the essential background information and protocols for investigating cell cell function, including, for example, investigations of cellular transport, receptors and gene expression. This is the essential guide to cell biology for researchers new to the field.