This chapter, part of a broader work on the conservation of historic monuments, studies the different aspects and financial risks involved in a conservation project. The author warns against incomplete knowledge of the monument or site to be restored or false cost estimates, and stresses the need for good planning in terms of human resources and materials. This chapter, as well as the others of the book, is rich in practical details and technical notes. This work contains an English glossary of useful construction terms. -- AATA