diff --git a/src/calibre/debug.py b/src/calibre/debug.py
index a9387fbe4d..ca344c39c3 100644
--- a/src/calibre/debug.py
+++ b/src/calibre/debug.py
@@ -62,6 +62,12 @@ Everything after the -- is passed to the script.
             help='Inspect the MOBI file(s) at the specified path(s)')
     parser.add_option('-t', '--tweak-book', action='store_true',
             help='Launch the calibre Tweak Book tool in debug mode.')
+    parser.add_option('-x', '--explode-book', default=None,
+            help='Explode the book (exports the book as a collection of HTML '
+            'files and metadata, which you can edit using standard HTML '
+            'editing tools, and then rebuilds the file from the edited HTML. '
+            'Makes no additional changes to the HTML, unlike a full calibre '
+            'conversion).')
     parser.add_option('-s', '--shutdown-running-calibre', default=False,
             action='store_true',
             help=_('Cause a running calibre instance, if any, to be'
@@ -247,6 +253,9 @@ def main(args=sys.argv):
     elif opts.tweak_book:
         from calibre.gui2.tweak_book.main import main
         main(['ebook-tweak'] + args[1:])
+    elif opts.explode_book:
+        from calibre.ebooks.tweak import tweak
+        tweak(opts.explode_book)
     elif opts.test_build:
         from calibre.test_build import test
         test()