This book is available as a single html page:
http://home.datacomm.ch/kerguelen/monadology/monadology.html
Useful book for the modern armchair philosopher.
Alternative to the Newtonian paradigm.
I'm about halfway through, so I'll spout off my understanding.
There is "perfect" sequence of events, symbolically described, somewhat like a computer program, but not limited by a programming language. The sequence is perhaps infinite. The sequence is self-contained... cannot be influenced by anything else. Leibniz calls this sequence God.
All other entities contain some transformation of the God sequence. The transformation is a projection from higher-dimension events to lower-dimension events, causing "imperfections." The other entities exist to become aware of limited segments of the God sequence. This awareness is not always direct. It may come about through unpleasant means, for example "contraction."
(Partial) understanding experienced by the limited entities is a kind of resonance with the God entity.
Well... my review seems to depart a little from the actual text.
The second half of the Monadology is amazingly consistent with Davd Bohm's "Wholeness and the Implicate Order".
Quantum rendering (qwendering), is the method for keeping the "created" instance monads in sync with the God monad. It appears to be an iterative process.