Most of Thayse 1989 and Thayse 1991, and a good
deal of Brachman et al. are devoted to specifying logical systems
central to AI. After 
and 
are established (and we
assume they now are for our readers, by virtue of the relevant material
presented above), the standard route is to move beyond them
by describing propositional modal logic (which we'll denote by 
),
pausing to consider what this new logical system might be good for,
and then proceeding to richer logical systems.
This route is competently followed in Thayse 1989 and Thayse 1991
essentially as follows.