The development of the langua;le Pascal is based on two principal aims. The first is to make available a language suitable to teach programming as a systematic di~cipline based on certain fundamental concepts clearly and naturally rellected by the language. The second is to develop implementations of this language that are both reliable and efficient on presently available lomputers. 

The desire for a new language for the purpose of teaching programming is due to my dissatl" faction with the presently used major languages whose features and co lstruCts too often cannot be explained logically and convincingly at d that too often defy systematic reasoning. Along with this dissa' isfaction goes my conviction that the language in which students are t(.1 ught to express their ideas profoundly influences their habits of though t and invention, and that the disorder governing these languages Ilirectly imposes itself onto the programming style of the students. 

There is of course plenty of reason to be cautious with the introduction of yet another prog-amming language, and the objection against teaching programming ill a language which is not widely used and accepted has undoubtedly ..,ome justification, at least based on short-term commercial reasoning. However, the choice of a language for teaching based on its widvspread acceptance and availability, together with the fact that the Ian ~uage most widely taught is therefore going to be the one most widt Iy used, forms the safest recipe for stagnation in a subject of sucl profound pedagogical influence. I consider it therefore well worth ,\'hile to make an effort to break this vicious circle. 

Of course a new language sh, IU III not be developed just for the sake of novelty; existing language ,; should be used as a basis for development wherever they mt: .~,t the criteria mentioned and do not impede a systematic structure. In I hat sense Algol 60 was used as a basis for Pascal, since it meets the dl mands with respect to teaching to a much higher degree than any other standard language. Thus the principles of structuring, and in f.tct the form of expressions, are copied from Algol 60. It was, however, Ilot deemed appropriate to adopt Algol 60 as a subset of Pascal; certail construction principles, particularly 

