Any resources about threading problems?

[Bill Medland]

Does anyone know any site or book or something with a decent discussion about 
the problems of the different threading models and their implementations?

In the Developer's Guide in section 8.3 there are references to "the threading 
chapter".  Is this a section that has not yet been written?

As I understand it we (in the pthreads version) "override the native pthreads 
library".  What does this mean?

I am trying to research the issues associated with threading so that I 
understand the complications.  The fact that Linux has two models and that 
Wine, FreeDCE and Samba (that I know of) seem to have found it necessary to 
bypass/hack/modify/override them indicates to me that there is something to 
understand.