Not often we hear about CSP here. I did my doctorate in it (Hoare was the head of department at the time). Are you using CSP for something real?
For those that wonder what we're wittering on about, visit http://www.cs.kent.ac.uk/teaching/07/modules/CO/6/31/slides/ and read these PDF slides in this order.
motivation.pdf -- just pages 1-39
basics.pdf
applying.pdf
choice.pdf
replicators.pdf
protocol.pdf
shared-etc.pdf
Ignore the crufty Occam (Transputer anyone?) syntax, just concentrate on the concepts. Although some of the PDFs seem to have many pages, often a page is the same as the previous with a minor change; they're slides!