THE MYSTERIUM COSMOGRAPHICUM, KEPLER’S NESTED SOLIDS AS THE BASIS OF PLANETARY ORBITS
Prodromus dissertationum cosmographicarum, continens Mysterium Cosmographicum de admirabili proportione orbium coelestium: deque causis coelorum numeri, magnitudinis, motuumque periodicorum genuinis & propriis, demonstratum per quinque regularia corpora goemetrica... Addita est erudita Narratio M. Georgii Ioachimi Rhetici, de Libris Revolutionum ... Item, eiusdem Ioannis Kepleri pro suo opere Harmonices Mundi apologia adversus demonstrationem analyticam Cl. V. D. Roberti de Fluctibus
Frankfurt: recusus typis Erasmi Kempferi, sumptibus Godefridi Tampachii, 1621
Folio: ):(4 A–V4; a–e4 f6 (–f6, blank), 109 of 110 leaves, pp.  163  (last page blank); 50. Woodcut initials, woodcut diagrams in the text; separate titlepages to the Rheticus dated 1621 (but the register and pagination continuous) and to the ‘Apologia’, dated 1622 with large woodcut printer’s device (on a1, starting the second register and pagination sequence).
5 leaves of plates: an engraving signed Christophorus Leibfried. ff. Tübing: 1597' (at p. 26) and 4 large woodcuts with letterpress headings and captions (2 at p. 18 and at pp. 54 and 56).
Condition: 318 x 197mm. Worm holes and tracks in the upper and lower margins, not affecting the text but touching a few lines and letters in the last two plates; quite heavy waterstaining throughout.
Binding: Contemporary British blind-ruled calf, old rebacking with most of the original spine preserved. Endleaves at front and back removed.
Provenance: ‘Dupplin Castle R. 175.10 and an earlier? shelf mark 'H. C.31' scored out and replaced with 'H. 7.3.’, both inside front board. Dupplin Castle, seat of the Hay Earls of Kinnoull, is a mansion house in Strathearn, Perth and Kinross, built in 1828–32 to replace an earlier castle destroyed by fire; the mansion later became the home of the Perth whisky baron John Dewar, Lord Forteviot (1856–1929); Walter Pagel (1896–1983), inscribed in his hand for his son Bernard (1930–2007) in 1957.
Second, enlarged edition (first 1596), containing, as in the first edition, a reprint of Rheticus Narratio prima (first 1540), and issued with the first edition of Kepler’s Pro suo Opere Harmonices Mundia apologia.
Bibliography: Caspar 67 and 68.
Kepler’s first book, usually referred to as ‘Mysterium Cosmographicum’ is a Copernican treatise which set the course for his life’s work. It contains Kepler’s theory that the orbit of each of the five planets is determined by the circumference of the five platonic solids nested one inside the other. This is illustrated in the famous engraved plate.
As well as Kepler’s own introductory chapter expounding and defending the Copernican theory, the book contains a reprint of Rheticus’ Naratio prima, the first announcement of the Copernican theory, first published in 1540, before De revolutionibus in 1543. This second edition contains Kepler’s additional notes reflecting the development of his thinking in the intervening 25 years. Also appended is the first edition of Kepler’s response to attacks by Robert Fludd on his Harmonices mundi of 1619.
The illustration of the nested solids is a fine engraving, copied in reverse from the engraving that appeared in the first edition of 1596, and still bearing the date 1597 (it is not clear why the engraving was dated a year after the date on the titlepage of the book).
‘Quixotic or chimerical as Kepler's polyhedrons may appear today, we must remember the revolutionary context in which they were proposed. The Mysterium cosmographicum was essentially the first unabashedly Copernican treatise since De revolutionibus itself; without a sun-centered universe the entire rationale of his book would have collapsed... After announcing his celebrated nest of spheres and regular solids, which to him explained the spacing of the planets, he turned to the search for the basic cause of the regularities in the periods... Although the principal idea of the Mysterium cosmographicum was erroneous, Kepler established himself as the first, and until Descartes the only, scientist to demand physical explanations for celestial phenomena. Seldom in history has so wrong a book been so seminal in directing the future course of science.’ (Owen Gingerich, DSB, 7: 291–3.)