Every year since 1909, the Unsearchable Riches magazine has been bound into a hardcopy book.  The original Unsearchable Riches volumes were not organized by calendar year. Volume 1 was 1909-1910. This continued through Volume 14 which was 1922-1923. Beginning with volume 15, they were organized by calendar year. Volume 15 was 1924 and volume 106 was 2015. As a general rule, once they became calendar years, simply add 9 to the volume to determine which year it was, with the first 14 volumes being the exception to that rule. Therefore volume 15 + 9 = 1924. The price for combined volume 109-110 is individually priced due to the rising cost of binding a book.  The price of this volume covers only our cost for the bookbinding.  Covering the cost of its printing as well would make the price even higher.