This text is concerned with the storage of networks of objects and procedures in a database which can be re-used by others. Referred to as data-intensive programming in the large [0], it combines techniques from object-oriented progamming and database research on long-term storage of large numbers of objects. The book stresses a particular feature from database theory known as Semantic Data Modelling, which offers powerful semantic constructs, appropriate for describing data objects. A particular semantic model, the Functional Data Model is cited because it incorporates the programming language Daplex.