The Gmelin Formula Index and its First Supplement covered those volumes of the Eighth Edition of the Gmelin Handbook which had been issued up to the end of 1979. The present Second Supplement updates the Index by inclusion of the volumes which appeared until the end of 1987. With this Second Supplement all compounds described in the Gmelin Handbook of Inorganic Chemistry in the period between 1922 and 1987 can be located. The basic structure of the Formula Index remained the same as in the previous editions. Computer techniques were employed in the preparation and print of the Second Supple ment. The data acquisition, sorting and further data handling were performed with the aid of a suite of computer programs developed by staff members of the former" Online Group" of the Gmelin Institute, now at Chemplex GmbH, and the printer, "Universitätsdruckerei H. Stürtz AG, Würzburg ". The present Second Supplement is intended to be the last one which is issued in printed form. The cumulated contents of the Index and its Supplements are contained in the Gmelin Formula Index (GFI) database wh ich is available to the scientific community via STN. This database will be updated annually to reflect the published Handbook volumes as close as possible.