The original series was published in 8 volumes, but the publisher pulled the plug on the planned ninth book, so the ending was very rushed and most people agree that the 8th volume was the weakest, souring many on the entire series. It looks like this will be rectified in the new versions, as new material has been written to fill in the missing gaps.
- The Middle Kingdom (1989)
- The Broken Wheel (1990)
- The White Mountain (1992)
- The Stone Within (1993)
- Beneath the Tree of Heaven (1994)
- White Moon, Red Dragon (1994)
- Days of Bitter Strength (1997)
- The Marriage of the Living Dark (1999)
You can get these pretty readily on eBay and in used bookstores, except for The Marriage of the Living Dark, which had a much smaller print run and may cost you a kidney or two to acquire.
I would suggest waiting for the new revised reprints to experience this phenomenal series.