Since the author's original books are rarely published as continuing editions, most references to his books are from this collection. Unfortunately, a dual page-numbering scheme pervades this compendium – the number of the original book, and the page number of the compendium (within each volume number). Thus, the reader will find references to 'RK' page numbers and also the book page numbers. In another unfortunate twist, individual books are typeset again when they are made a part of this compendium, and new page numbers were assigned, rather than the last printed edition's page numbers. This happens with each new edition of the compendium (last one in 1984). To compound the problem further, in the PDF versions of this collection, the PDF page numbers may not also match the RK page numbers.