CONTENTS–The functional centre of the ribosomal RNA–Site‐directed cross‐linking – Cross‐links to tRNA – Cross‐links to mRNA – Cross‐links to the growing peptide chain – Other data at the functional centre – Methodology for localizing site‐directed cross‐links on ribosomal RNA–Topographical data for the complete 16S and 23S RNA molecules–16S RNA – What is nucleotide resolution?– 23S RNA–Ribosomal morphology–Electron microscopy of ribosomes and subunits – The R versus S configuration of two tRNA molecules–Problems with proteins–Uncertainties in fitting the 16S RNA to the 30S protein distribution – The 530 loop controversy–Our new 16S RNA model – Future prospects