The availability of an excellent and freely available molecular visualisation package authored by Roger Sayle-RasMol, coupled to the protein data bank (PDB) resource of molecular structure data makes the visualisation and manipulation of molecular data accessible to the Internet, community. Tutorials based on almost any protein deposited in the PDB can be utilised as an aid to understand bio-molecular modelling. The utility of these resources is illustrated for modelling and visualisation of HEW lysozyme. (C) 2001 IUBMB. Published by Elsevier Science Ltd. All rights reserved.