The present volume III/48 is a supplement to the earlier volumes III/20, III/31 and III/39 of nuclear quadrupole resonance spectroscopy (NQRS) data of condensed substances. Compilation of the original data in the form of numeric database is continuing and the present supplement covers a period from August, 1995 to the end of 2006. There are 2,535 entries in this supplement and, therefore, the four volumes together provide about 14,400 data which have been published since the discovery of NQRS in 1951 until the end of 2006. Due to the large amount of data the present supplement is published in two subvolumes, III/48A (1270 entries) and III/48B (1265 entries), respectively. The present supplement gives NQRS data of substances new to the database as well as new and/or revised data for substances already reported in the previous volumes. In the latter case, not only the changes are provided but also the entire revised entry is reproduced so that the reader need not look for the previous entry in earlier volumes for the same substance. Thus, readers are advised to try to find the substance of interest first in this volume III/48 and then proceed backwards to volumes III/39, III/31 and III/20. Also, for the sake of readers' convenience, Chapters 1 and 2 have been reproduced from volume III/39 (except for the eigenvalue tables in Sects. 2. 8 through to 2. 10 of volume III/39), with minor modifications that adapt to this supplement.