0. Introduction.- 0. Introduction.- 0.1. Aims and principles of design.- 0.1.1. Completeness and clarity of description.- 0.1.2. Orthogonal design.- 0.1.3. Security.- 0.1.4. Efficiency.- 0.2. Comparison with ALGOL 60.- 0.3. Comparison with the language defined in 1968.- 0.4. Changes in the method of description.- I Preliminary definitions.- 1. Language and metalanguage.- 1.1. The method of description.- 1.1.1. Introduction.- 1.1.2. Pragmatics.- 1.1.3. The syntax of the strict language.- 1.1.3.1. Protonotions.- 1.1.3.2. Production rules and production trees.- 1.1.3.3. Metaproduction rules and simple substitution.- 1.1.3.4. Hyper-rules and consistent substitution.- 1.1.4. The semantics.- 1.1.4.1. Hypernotions, designation and envelopment.- 1.1.4.2. Paranotions.- 1.1.4.3. Undefined.- 1.1.5. Translations and variants.- 1.2. General metaproduction rules.- 1.3. General hyper-rules.- 2. The computer and the program.- 2.1. Terminology.- 2.1.1. Objects.- 2.1.1.1. Values, locales, environs and scenes.- 2.1.1.2. Modes.- 2.1.1.3. Scopes.- 2.1.2. Relationships.- 2.1.3. Values.- 2.1.3.1. Plain values.- 2.1.3.2. Names.- 2.1.3.3. Structured values.- 2.1.3.4. Multiple values.- 2.1.3.5. Routines.- 2.1.3.6. Acceptability of values.- 2.1.4. Actions.- 2.1.4.1. Elaboration.- 2.1.4.2. Serial and collateral actions.- 2.1.4.3. Initiation, completion and termination.- 2.1.5. Abbreviations.- 2.2. The program.- II Fundamental constructions.- 3. Clauses.- 3.1. Closed clauses.- 3.2. Serial clauses.- 3.3. Collateral and parallel clauses.- 3.4. Choice clauses.- 3.5. Loop clauses.- 4. Declarations, declarers and indicators.- 4.1. Declarations.- 4.2. Mode declarations.- 4.3. Priority declarations.- 4.4. Identifier declarations.- 4.5. Operation declarations.- 4.6. Declarers.- 4.7. Relationships between modes.- 4.8. Indicators and field selectors.- 5. Units.- 5.1. Syntax.- 5.2. Units associated with names.- 5.2.1. Assignations.- 5.2.2. Identity relations.- 5.2.3. Generators.- 5.2.4. Nihils.- 5.3. Unitlƒ%