diff --git a/doc/quickbook/zip_iterator.qbk b/doc/quickbook/zip_iterator.qbk
index 7f97772..ccd8689 100644
--- a/doc/quickbook/zip_iterator.qbk
+++ b/doc/quickbook/zip_iterator.qbk
@@ -8,6 +8,16 @@ the zip iterator moves all the iterators in parallel.
 Dereferencing the zip iterator returns a tuple that contains
 the results of dereferencing the individual iterators. 
 
+The tuple of iterators is now implemented in terms of a Boost fusion sequence. 
+Because of this the 'tuple' may be any Boost fusion sequence and, for backwards
+compatibility through a Boost fusion sequence adapter, a Boost tuple. Because the 
+'tuple' may be any boost::fusion sequence the 'tuple' may also be any type for which a 
+Boost fusion adapter exists. This includes, among others, a std::tuple and a std::pair.
+Just remember to include the appropriate Boost fusion adapter header files for these
+other Boost fusion adapters. The zip_iterator header file already includes the
+Boost fusion adapter header file for Boost tuple, so you need not include it yourself
+to use a Boost tuple as your 'tuple'.
+
 [section:zip_example Example]
 
 There are two main types of applications of the `zip_iterator`. The first