Amazon.com description: Product Description: Mr. Willis (a.k.a. Brewer-Ward), the author of The House of Hapsburg: A Genealogy of the Descendants of Empress Maria Theresia, here turns his attention to the 17th-century French monarch Louis XIII. Louis's genealogical importance is that he is the common male line ancestor of all remaining royal lines of the House of Bourbon, which at its height attained hegemony not only in France but also over the Austro-Hungarian Empire; the Kingdoms of Spain, Portugal, and the Two Sicilies; the Duchies of Parma and Modena; and the Grand Duchy of Tuscany.

In this very detailed, liberally illustrated volume Mr. Willis has endeavored to trace out every line of descent from Louis XIII, both male and female, legitimate and illegitimate. The various Bourbon lines are organized into chapters corresponding to each country or duchy controlled by the Bourbons, and the information is presented in outline format. The author has made every attempt to include the following information about each descendant of Louis XIII: his/her date and place of birth, date and place of death, full names and titles, and dates and places of all marriages. Spouses of descendants are identified by full name and title, date and place of birth and death, parents' names, including the mother's maiden name, and additional spouses, if any. In the case of illegitimate children numbered among Louis XIII's descendants, Mr. Willis includes all children who were recognized either by the parent in question, the courts, or other family members. Besides providing a surname reference to the roughly 100,000 descendants, Mr. Willis has devised an extensive cross-referencing system to connect descendants who intermarried. The author has also included a bibliography and an appendix to the lineages, which shows the connections between Louis' descendants and other sovereign houses. In conclusion, The Descendants of Louis XIII, King of France is a stunning new contribution to the field of royal genealogy.