The Judo Advantage by  Steve Scott  is an excellent read, the presents a simple yet profound approach to teaching the principles of Judo  that will  help to give all martial artists an advantage in their art , it is very well illustrated and ideal for all grappling styles covering disciplines such as Judo, sambo , BJJ and Olympic wrestling,  with In-depth analysis of stances, kazushi, throws, takedowns, transitions & footwork.