Explain that the hierarchy is not cleanly divided into packages - two
people (at least) have so far been confused that System.Posix.Types is
in base but System.Posix is in unix.
<BODY>
<H1>Haskell Hierarchical Libraries</H1>
- <P>The libraries are divided into several <EM>packages</EM>:</P>
+ <P>The libraries are divided into several <EM>packages</EM>.
+ NOTE: there is not always a clean division between packages in the
+ hierarchy, which means a node and its children might be in
+ different packages. If you're looking for a specific module, try
+ all the packages below.</P>
<DL>
<DT>