RARE descriptive monograph on the astronomical clock of the Lund cathedral, the `Horologium mirabile Lundense`, made around 1424, in storage since 1837, and restored and put back in its place in 1923 under the supervision of the author, Theodor Wählin (1864-1948), the renowned Swedish architect and resident architect at Lund Cathedral from 1902. 210x145mm. 33 pages. Illustrated softcover. Cover stained and yellowing. Pen marks on front cover corners near spine. Sticker residue on front cover bottom corner. Cover and pages upper corner and edge somewhat wrinkled. Spine bottom edge detached from front cover and worn. Ex-library copy with stamp and pen/pencil marks on title page verso and page 25, and stamp on last page. Pages yellowing. [SUMMARY]: This extremely rare monograph on the unique Lund Cathedral medieval clock has suffered some mostly external damage, but is still in good reading condition.