Most pre-modern Arabic book-titles have a bipartite, generally rhyming stru
cture, in which both parts have, also in general, a complete and independen
t significance. This conventional structure seems to be ignored by those wh
o translate the second part as an extension of the first one. The reason fo
r this division in two parts is to provide the book with a short, easy to l
earn title, contained in the first half of the entire title, and a "sub-hea
ding," which is contained in the second half, introducing the general refer
ence to the topic itself.