Elaborate a bit on the MOP

lib/Language/mop.pod

@@ -102,4 +102,38 @@ The presence of a C<Scalar> object indicates that the object is "itemized".
     say (1, 2, 3).VAR ~~ Scalar; # False
     say [1, 2, 3].VAR ~~ Scalar; # True
 
+=head1 Structure of the meta object system
+
+B<Note:> this documentation largely reflects the meta object system as
+implemented by the L<Rakudo Perl 6 compiler|http://rakudo.org/>, since the
+L<design document|http://design.perl6.org/> are very light on details.
+
+For each type declarator key word, such as C<class>, C<role>, C<enum>,
+C<module>, C<package>, C<grammar> or C<subset>, there is a separate meta
+class in the C<Metamodel::> namespace. (Rakudo implements them in the
+C<Perl6::Metamodel::> namespace, and then maps C<Perl6::Metamodel> to
+C<Metamodel>).
+
+Many of the these meta classes share common functionality. For example roles,
+grammars and classes can all contain methods and attributes, and can do roles.
+This shared functionality is implemented in roles which are composed into the
+appropriate meta classes. For example
+L<role Metamodel::RoleContainer|/type/Metamodel::RoleContainer> implements the
+functionality that a type can hold roles, and
+L<Metamodel::ClassHOW|/type/Metamodel::ClassHOW>, which is the meta class
+behind the C<class> keyword, does this role.
+
+=head2 Bootstrapping concerns
+
+You might wonder how C<Metamodel::ClassHOW> can be a class, when being a class
+is defined in terms of C<Metamodel::ClassHOW>, or how the roles responsible
+for role handling can be roles. The answer is I<by magic>.
+
+Just kidding. Bootstrapping is implementation specific. Rakudo does it by
+using the object system of the language in which itself is implemented, which
+happens to be (nearly) a subset of Perl 6: NQP, Not Quite Perl. NQP has a
+primitive, class-like kind called C<knowhow>, which is used to bootstrap its
+own classes and roles implementation. C<knowhow> is built on primitives that
+the virtual machine under NQP provides.
+
 =end pod

lib/Language/objects.pod

@@ -621,6 +621,7 @@ To get rid of using the same object twice, there is a shortcut:
     say 1.HOW.name(1);                  # Int
 
 See L<Metamodel::ClassHOW|/type/Metamodel::ClassHOW> for documentation of
-the meta class of C<class>.
+the meta class of C<class>, and also the L<general documentation on the meta
+object protocol|/language/mop>.
 
 =end pod