The present volume contains manuscripts of lectures or topics related to the lectures which were given at the conference on "Inverse Problems" at the mathematical Research Institute at Oberwolfach. The conference took place during the week of May 18-24, 1986, and was managed by the editors. Recalling Professor Joseph Keller's paper entitled Inverse Problems, American Mathematical Monthly, 83 (1976), we give two direct quotes. "We call two problems...