"The Featherweight 221 and I" by David McCallum. This bestselling book has everything you need to know to maintain, repair and restore your Featherweight machine on your own. It has a lay-flat, spiral binding which makes it easy to use. The pages are printed single-sided for taking notes or sketches as you work. It has well illustrated technical drawings to assist you with each step as you learn to clean, rebuild, and even "fumigate" the machine's carrying case.