The Sacrobosco editions constitute a textual tradition wherein innovation owed to the interaction of two types of actors: borrowers, responsible for chains of related editions, and innovators, who wrote relatively original commentaries. This can be observed in the "in-octavo tradition," a series of editions printed in several European towns, which began with Apianus's 1526 Sphaera and endured until the seventeenth century. Different kinds of innovation were produced in it (concerning the layout, the illustration, and different kinds of textual additions). This successful attempt at standardization produced a kind of manual that always retained an essential part of its original features while remaining capable of evolution. This evolution was due to close cooperation between the publishers and mathematicians, and to the fact that the former, with a few exceptions, kept control over the process, and combined innovation with the artful practice of reusing borrowed material. Divisio secundum accidens sphaerae Prooemium auctoris Diffinitio sphaerae. Cap. 1 Quae forma sit mundi Quae forma sit mundi De coeli revolutione De coeli rotunditate Quod Terra sit rotunda Quod aqua sit rotunda Quod aqua sit rotunda Quod Terra sit centrum mundi De immobilitate Terrae De quantitate absoluta Terrae De circulis ex quibus sphaera materialis componitur: et illa supercaelestis quae per istam imaginatur componi intelligitur. Capitulum secundum Capitulum secundum De circulis ex quibus sphaera materialis componitur: et illa supercaelestis (quae per istam imaginatur) componi intelligitur De zodiaco circulo De duobus coluris De meridiano et horizonte De quatuor circulis minoribus De zodiaco circulo De duobus coluris De meridiano et horizonte De quatuor circulis minoribus De quinque zonis * De caracteribus sphaerae decimae vel nonae et stellationibus octavae * Quae signa quibus circulis dividantur * Sequuntur figurae septentrionales * Figurae Australes a De ortu et occasu signorum et diversitate dierum et noctium et de diversitate climatum. Capitulum tertium Capitulum tertium De ortu et occasu signorum, de diversitate dierum et noctium, et de diversitate climatum De ortu et occasu signorum secundum astrologos De diversitate dierum et noctium quae sit habitantibus in diversis locis terrae