Two chapters of this volume deal with closely related tricyclic heteromatic systems. The last comprehensive review of the dibenzofurans appeared in 1951; the subject is now updated by Sargent and Stransky. Carbazoles have also not been comprehensively reviewed recently; this has been done in this volume by Joule.
The chemistry of four-membered rings containing one sulfur atom — the thietanes and their derivatives — is covered by Ried and Heinz, who update earlier surveys that appeared about 20 years ago.
The bipyridines, of considerable industrial and theoretical interest, are comprehensively reviewed for the first time by Summers.
Two chapters, dealing with 2H- and 4H- imidazoles by Sammes and the series editor, continue and conclude the series on nonaromatic azoles, which included contributions on 2H- and 3H- pyrroles (in Volume 33) and on 3Н- and 4H- pyrazoles (in Volume 34).
Most of the chapters in this volume cover the literature up through 1982.