Deleted chapters, parts, front matter, back matter, and glossary terms can be recovered within 30 days of when they're first deleted, or "Trashed." After 30 days, trashed posts are permanently deleted.
To recover a post from the Trash:
1. Go to Organize > Trash from the left sidebar menu in Pressbooks
2. Identify the post you'd like to recover
3. Click "Restore"
Restored chapters, parts, front matter, and back matter will appear on your Organize page again. Restored glossary terms will reappear on the Glossary Terms page.