many of the e-texts contain poetry, or verse of some type, so your system must be able to handle silliness like that.
some poems want to be left-justified, so you should be able to handle that:
a haiku for you (by bowerbird intelligentleman)
haiku have three lines and seventeen syllables five, seven, and five
other poems want to be centered instead:
t.v. will eat you
(by bowerbird intelligentleman)
t.v. will eat you
out of a satellite dish
with a tuning fork
and some poems want to alternate...
six spaces at the start of this line 12 spaces at the start of this line six spaces at the start of this line 12 spaces at the start of this line six spaces at the start of this line 12 spaces at the start of this line six spaces at the start of this line 12 spaces at the start of this line
and some poems want to get fweaky!
six spaces at the start of this line ten spaces at the start of this line 14 spaces at the start of this line 18 spaces at the start of this line 22 spaces at the start of this line 26 spaces at the start of this line 22 spaces at the start of this line 18 spaces at the start of this line 14 spaces at the start of this line ten spaces at the start of this line six spaces at the start of this line
in general, lines of a poem prefer to stay together, that is, to be kept all on a page whenever possible, so your system should attempt to accomplish that...
if it's not possible to keep the whole poem on a page, try to make the page-break occur between the verses...