This 1st Edition was printed after Christiaan Huygens' presentation in 1657 of his design for a swing pendulum clock. It contains a fold out plate of his design as well as his description, including manuscript ink errata.

A small book of great importance to the history of horology and with only two known copies in existence; the other being in the Bodleian, is also exceedingly rare. The book was however, fragile in several places. At some point prior to the current client's ownership, an attempt to remove the Sion College Library marks (Sion was in the 17th Century London's copyright library) by bleaching and mechanical rubbing had taken place. This had left aesthetically unpleasant stains and more importantly very fragile paper on the titles pages and on the fold-out diagram. In addition the glue from the original binding had stiffened and was creating false hinges around the thin paper of the spine folds.

After we confirmed the provenance of the book was bona fide, it was decided to remove the book from its original binding, clean and repair the spine folds and to wash and line the pages affected by the bleaching and thinning of the paper around the old library marks. Once these treatments were complete the book was rebound into an adhesive free limp vellum binding in the Dutch style, using Dutch vellum. In addition an English translation was printed and bound along with 12 facsimiles of the original text which were all bound in full calf bindings with gold tooled covers. The idea being that the original could be stored safely and used rarely, whilst the facsimiles and translation stood in for regular use and research. A facsimile and the translation were housed in a 3-drawer box with the original.