<title> SUMMARY </title>The present catalogue includes the descriptions of 147 trade publications, dealing with scientific instruments, belonging to the Library of the Palermo Astronomical Observatory. This collection is a rather conspicuous one, especially if one considers the traditionally «ephemeral» nature of such material. A number of catalogues (73) were published before 1915, while the remaining span up to 1972. For consistency with the Handlist of Scientific Instrument-Makers Trade Catalogues, 1600-1914 published in 1990 by R. G. W. Anderson, J. Burnett, B. Gee, of which the present catalogue is meant to be an addendum, we have followed the same temporal partition. Items are listed in alphabetical order by makers' name, and in within publications by the same maker, in chronological order. Descriptions follow the ISBD rules, i.e. they are divided into a sequence of areas, separated by conventional punctuation. Every effort has been made to give publications dates, even though these are sometimes approximative, being desumed from information internal to the text.