Annual Reports in Inorganic and General Syntheses–1975 presents an annual review of synthetically useful information that would prove beneficial to nearly all organic chemists, both specialist and nonspecialist in synthesis. It should help relieve some of the information storage burden of the specialist and should aid the nonspecialist who is seeking help with a specific problem to become rapidly aware of recent synthetic advances. This is the fourth volume of "ARIGS" and is organized along the lines used for the last volume. The authors were encouraged to use synthetic aspects as their primary guideline for the arrangement and preservation of the information; however, an occasional deviation to include structural or mechanistic features seemed to be justified in order to reflect the particular features of a given element's chemistry. Complex hydrides were dealt with under the particular elements. As a consequence there is no chapter on simple and complex metal hydrides of main groups I, II, and III in the present volume. As in previous issues of ARIGS, this volume presents an article of a timely subject of special interest. This year's special feature is the "Synthesis of Radiopharmaceuticals by the Reduction of 99m TcO4-."