This chapter briefly describes the history of immunoscintigraphy and radioimmunotherapy of prostate cancer starting with monoclonal antibodies (MoAb) against prostatic acid phosphatase in the late 1980s and ending with anti-PSMA antibodies in the 2000s. The plot is based on our own journey even though no major breakthroughs happened. Although some commercial tracers were available, they did not make any success. Now the future is open for better MoAb applications, because the field is very active.