This article considers the various 100 % Reserve plans that have appeared since the interwar period and have been adapted in the following period. In all formulations of those schemes, Government liabilities (cash, central bank reserves and short-term Treasuries) back banks' sight deposits. The article briefly presents the six categories of plans. It highlights their common features as well as their differences, showing that the differences are more numerous than the common features. The criticisms voiced against the different formulations of 100 % Reserves are exposed. In spite of these criticisms, the article shown that the 100 % Reserve reform is becoming topical, with recent private sector, central banks and political initiatives that relate to it. Overall, the 100 % Reserve reform does not appear as a meaningful opportunity to improve the functioning of banking systems. Furthermore, at least, one of its variants could easily turn into a calamity. Fortunately, it is not that variant that is getting more topical.