Professor József Tóth had to leave Hungary, his homeland, in 1956, when the revolution collapsed. In Canada he became a well-known and respected hydrogeologist of world-wide reputation, whose professional activity triggered a fundamental turn in the develpoment of hydrogeology. On invitation he revisited Hungary in 1994 and since then has been in contact with Hungarian hydrogeologists. József Tóth resettled in Hungary in 2005, and he became honorary professor at Eötvös Loránd University, Budapest.
This book is dedicated to him and his activity in Hungary. It summarizes the results of the research projects he has contributed to at Eötvös Loránd University.