An ordinary 18th-century German law book. Quite plain. Not especially well printed. Not even a first edition, but rather a third. But wait, what have we here? This looks like a quarto, not a twelvemo. Ah! A former owner, some time in the late 18th century, evidently hired a binder to pull the original covers, reduce the text block to 153 discrete bifolia, window-mount each conjugate pair into the center of half of a much larger blank sheet, fold, collate, resew, and rebind to produce a stout quarto volume—all simply to increase the scribable marginal real estate. Which our former owner has taken full advantage of: nary a single page (excepting the prefatory matter and 30-odd pages of judgments at end) does not bear extensive scholarly notes in Latin in a tidy, legible hand. Some pages, especially those sections concerning the laws of succession, are filled, horror vacui, with expository annotations and corrections, citations of core law books, and neat sketches of various trees of consanguinity which mirror those printed in the adjacent text. According to Nicholas Pickwoad, window-mounting leaves into larger sheets is "the most sophisticated (and expensive) way" of altering a book to make room for a reader's notes.1 This cataloguer, who once labored as a restorer and binder, can attest to this, the ultimate challenge being to sufficiently pare both the edges of the pages and the windows into which they will be mounted so that the resulting volume does not swell where the natural overlap occurs. The unknown 18th-century binder has produced an exceptional example of the art, made to order for a diligent legal annotater. Of the highest interest to both the history of practical bookbinding and of German legal scholarship. Three copies in US libraries (Harvard Law, Yale Law, and Berkeley).
Stuttgart: Christian Gottlieb Rößlin, 1743.
Twelvemo, 137 x 78 mm (individual leaves), 200 x 164 mm (host leaves), 200 x 164 x 54 mm (resulting text block), 202 x 166 x 58 mm (binding). )(12, )(10, A-Z12, )(6, inserrted folding letterpress table after page 426. , 535,  ff. Late-18th-century vellum drummed over stiff boards, titled on back on red paper lettering-piece, edges stained vermilion. Binding quite worn and soiled, with tail half of spine torn away, and tail headband damaged. Structurally, the book remains sturdy and functional. Interior: Folding leaf with staining and tears (no loss); some marginal staining to final leaves; fingersoiling; some errant ink stains.
Custodial remark in Latin to title (and over into renewed margin): Autor sig Juris topici erat. [?] Bocer. This Bocer could be have been the owner of the book and the person responsible for its bespoke structure and extensive annotations. A later cataloguer's penciled notes in German to upper pastedown.
1Pickwoad, Nicholas, "Binders’ Gatherings," The Library, 7th Series, Vol. 15, No. 1 (March 2014), pp. 63–78.