Johnny Dangerous wrote:I should say also I have not read as much Mahayana sutra as the Pali stuff, should I start with Perfection Of Wisdom, and if I read this (or anything else), will it point me in the right direction, or is the question really just splitting hairs anyway?
Although based in the Buddha's teachings which can also be found in the Pali canon (Pali: suññatā), the ''doctrine" of śūnyatā is most fully formed in Mahāyāna teachings, specifically those of Nāgārjuna and the Mādhyamika. Buddha used the logic of suññatā to refute the view (dṛṣṭi) of a "self-essence" (svabhāva, literally, "self-being") or ātman. Basically, by showing the truth of dependent arising (pratītyasamutpāda) that all things that arise are dependent on the arising of other things, there is no such thing as "self-essence". Later, Nāgārjuna extended Buddha's logic to refute renewed and new views of ātman as well as using it to refute other "wrong views". There is also further development after Nāgārjuna by a long line of Buddhist logicians.
It is a lot of 'hair splitting', but many find it useful to develop an ability to follow the logic through the teachings. The Prajñāpāramitā (Perfection of Wisdom) sutras really do not lead through the logic, but rather concentrate on the logical 'outcome' of śūnyatā, which is the development of great compassion.
So, to understand the logic of śūnyatā, you might want to start with the work of Nāgārjuna and the numerous commentaries on his work.
Hope this helps.