The British Museum's collections contain artefacts composed from almost the whole range of materials known to mankind prior to this century, For more than 70 years, analysis has been a vital tool in the conservation of the museum's collections and recently thermoanalytical techniques have been shown to complement techniques existing within the museum's laboratories. Their major contribution to date has been in a project re-examining the firing process used as part of the conservation of an important collection of unfired clay tablets bearing cuneiform script from ancient Mesopotamia. Differential scanning calorimetry (DSC) has shown that the 130 000 plus tablets from 22 major sites should be treated with the same firing schedule. Together with thermogravimetyric analysis (TGA) and thermomechanical analysis (TMA), the results have indicated several beneficial modifications to the present firing schedule, the most important being the lowering of the firing temperature to avoid a damaging calcite decomposition reaction.