The restoration of Michelangelo's frescoes in the Sistine Chapel was begun in 1980 and will be completed in 1992. Fourteen lunettes and half the vault have been restored so far. The work is being carried out by the Laboratorio di Restauro of the Vatican Museums. It was impossible to rely on the literature about the technique of execution; recent technical and scientific research has confirmed that the paintings have indeed been done in <i>buon fresco</i>. Since no signs of transfer from cartoons were detected, Michelangelo's technique is once again characterized as supreme ( absolutely lucid, almost without second thoughts ) Damp from rain (holes in the roof) and the build-up of smoke from candles and braziers combined with layers of gum and glue used in past restorations are responsible for the formation of a dark glass-like skin on the frescoes. The problem of cleaning has been central; a mixed solvent made up of saturated solutions of ammonium bicarbonate and sodium bicarbonate, Desogen, carboxymethyl cellulose and water, with precise times of contact, has given acceptable results. This formula was developed by Paolo and Laura Mora. Future conservation of the frescoes will consist in controlling the microclimate of the Sistine Chapel. A minimum of reintegration is executed in watercolors, using the <i>tratteggio</i> technique.