Lot Essay
In his preface, the author of this commentary indicates that the diagrams present in the original work are drawn in red, whilst the author's own diagrams are drawn in black. The original work, probably by Tusi, al-Tadhkira fi 'ilm al-Hay'a is an attempt by the celebrated polymath to give a coherent and unified account of astronomy that would be useful for students of the subjects as well as non-specialists.