+
+
+class DocumentTextRevertForm(forms.Form):
+    """
+    Form for reverting document's text:
+
+        * revision - revision to revert to.
+        * comment - user's verbose comment; will be used in commit.
+
+    """
+
+    revision = forms.IntegerField(widget=forms.HiddenInput)
+
+    author_name = forms.CharField(
+        required=False,
+        label=_(u"Author"),
+        help_text=_(u"Your name"),
+    )
+
+    author_email = forms.EmailField(
+        required=False,
+        label=_(u"Author's email"),
+        help_text=_(u"Your email address, so we can show a gravatar :)"),
+    )
+
+    comment = forms.CharField(
+        required=True,
+        widget=forms.Textarea,
+        label=_(u"Your comments"),
+        help_text=_(u"Describe the reason for reverting."),
+    )
+
+
+class ChunkForm(forms.ModelForm):
+    """
+        Form used for editing a chunk.
+    """
+    user = forms.ModelChoiceField(queryset=
+        User.objects.annotate(count=Count('chunk')).
+        order_by('-count', 'last_name', 'first_name'))
+
+
+    class Meta:
+        model = Chunk
+        exclude = ['number']
+
+    def clean_slug(self):
+        slug = self.cleaned_data['slug']
+        try:
+            chunk = Chunk.objects.get(book=self.instance.book, slug=slug)
+        except Chunk.DoesNotExist:
+            return slug
+        if chunk == self.instance:
+            return slug
+        raise forms.ValidationError(_('Chunk with this slug already exists'))
+
+
+class ChunkAddForm(ChunkForm):
+    """
+        Form used for adding a chunk to a document.
+    """
+
+    def clean_slug(self):
+        slug = self.cleaned_data['slug']
+        try:
+            user = Chunk.objects.get(book=self.instance.book, slug=slug)
+        except Chunk.DoesNotExist:
+            return slug
+        raise forms.ValidationError(_('Chunk with this slug already exists'))
+
+
+
+
+class BookAppendForm(forms.Form):
+    """
+        Form for appending a book to another book.
+        It means moving all chunks from book A to book B and deleting A.
+    """
+
+    append_to = forms.ModelChoiceField(queryset=Book.objects.all(),
+        label=_("Append to"))
+
+
+class BookForm(forms.ModelForm):
+    """
+        Form used for editing a Book.
+    """
+
+    class Meta:
+        model = Book
+
+
+class ChooseMasterForm(forms.Form):
+    """
+        Form used for fixing the chunks in a book.
+    """
+
+    master = forms.ChoiceField(choices=((m, m) for m in MASTERS))