The last twenty years has seen the biggest revolution in the treatment of renal tract stone that has ever been experienced in the history of urolithiasis. The treatment of upper tract renal stone has progressed from the days of a very traumatic and morbid procedure to the relatively innocuous, walk in/walk out therapy of extracorporeal lithotripsy. This progression of events has resulted in a complete reappraisal of management of all types of urinary calculi. From an initial reluctance to treat many stones because of the trauma involved, we have now passed to a situation where smaller and asympto­ matic stones may be pre-emptively treated before the treatment of serious clinical problems. It is true to say that in Westemized societies the problem of urolithiasis has almost completely been solved by the advent of advanced technology. In this volume, attention is drawn to the fact that there are still persistent difficulties in treating urolithiasis in the less developed and less affluent societies. The differences in epidemiology of urolithiasis in various areas of the world are highlighted, noting a rapid decrease in the incidence of bladder calculi in impover­ ished areas where affluence increases. Coupled with this progression of affluence however is the well documented increase in the incidence of upper tract renal stones of oxalate nature. This scenario has been almost universal across all coun­ tries in the last few decades.