Dear mcaro and Frank Kuan,

if> The Abhidhamma was probably composed circa 300 - 500
if> years after Buddha╢s Parinibbana.

The various parts of Abhidhamma were composed in different times, so
it is more useful to consult the chronology of the Pali Canon:

http://sino-sv3.sino.uni-heidelberg.de/FULLTEXT/JR-ENG/bcl.htm

For example, Vibhanga, when examined, turns out to be very consistent
with the spirit and letter of Sutta-pitaka.

It is interesting that first Abhidhamma consisted of Patisambhidamagga
(as evidenced by references in Vimuttimagga), but later has grown and
changed.

Mettaya, Dimitry