Potential users of the telescope should submit their proposals via the web-based submission procedure described below (the preferred option) or, if this is not possible, send them by ``snail mail'' to the Observatory Director at Arecibo. In their proposal, they should describe the desired observations and give justifications for the scientific aims and the amount of telescope time requested. Proposals are accepted for 3 deadlines per year, and are evaluated by a panel of anonymous referees, associated with neither NAIC nor Cornell University.