This volume details the process of, and difficulties in, assembling the data: the source notes for every column in each sub-file for each of the Excel files A-P; with some fuller explanation of the heading; and particular notes for particular years in each column. There are also explanations, calculations and reasoning for particular estimates and how totals were arrived at. The reasoning for some totals and the inclusion of certain categories may be contested. I welcome such disagreements, suggestions of sources which I may have missed, and correction of straightforward mistakes. There is no other work of this magnitude. This is a workbook for future scholars to peruse and amend. I will provide amendments as necessary. The painstaking research initially involved going through the British Parliamentary Papers (BPP) from 1830, item by item, and reconstructing 'country-specific estimates from the available empirical evidence'. The second part of this volume provides a guide to what was considered, even if not used, 1830-1920 in the British Parliamentary Papers. The primary other sources emerged from this process, particularly for the first phase and the first half of the second phase. The data to which the sources in this work refer, and which are the statistical basis of the first volume, "The Key to all Mythologies". For queries contact [email protected]