Legality is the corner-stone of the law-state ideology. That legality is upheld is a necessary condition for the realisation of the four basic law-state values. Four legality principles are presented and discussed. A key concept in this connection is “compliance with the law”, which is investigated thoroughly. Technical devices in the hands of law-appliers as well as legislators in order to guarantee legality are presented. It is important to realise that legislators at times can go too far in the direction of legality (Summum ius, summa iniuria), thereby in fact violating some law-state value. The limits of legality is devoted a section of its own. Finally, it is important to bring to the fore that legalism sometimes demands subordination of certain spheres of law, where legality is important, to legislation. Of special importance is the subordination of the activities of the highest state organs to legislation (constitutionalism).