The Sixth Book

From Apollonius to Attalus: peace be on you. I have sent you the sixth book of the Conics. My aim in it is to report on conic sections which are equal to each other and those unequal to each other, and on those similar to each other and dissimilar to each other, and on segments of conic sections. In this we have enunciated more than what was composed by others among our predecessors. In this Book there is also how to find a section in a given right cone equal to a given section, and how to find a right cone, containing a given conic section, similar to a given cone. What we have stated on this [subject] is fuller and clearer than the statements of our predecessors. Farewell.