The Hardy inequality has a fascinating past and will have (hopefully) also a fascinating future. Here, the authors present some important steps of the development of the classical Hardy inequality , of its early weighted generalizations (i.e. furnished with general weights) and of its various modifications and extensions. Besides the continuous (i.e. integral) case, the (originally) discrete one (i.e. for sequences) is dealt with. Eighteen theorems are formulated, most of them with proof. Although the choice of material is a matter of personal taste and knowledge, the authors intended to include as many results as possible, using papers published up to 2005.