The planning and actual work involved in stone conservation can be illustrated by the example of the Alte Pinakothek in Munich an art gallery of international standing. The building was constructed by the famous Munich architect, Leo von Klenze, in the years 1826 to 1936. It was built of sandstone and brick. Most of the damage is to the sandstone. World War II also caused great damage which was only repaired provisionally. About 10 years ago, the authorities decided to restore and conserve the building. It was decided to conserve the building in its current state, i.e., keeping the stone repair work to a minimum. We started the conservation tests in 1974. In 1975, we laid out the first testing area and determined a possible method of conservation. This method was transferred to larger areas in 1977 and 1978. The total con servation process could start in 1984 because of the excellent results obtained on the testing areas.