There is. On the Apple Support page I learned how easy it is:
Twenty minutes later the task was done. And as an added bonus, while I was taking the time to re-title files I also took the opportunity to purge a couple I didn't need any more.
- Step 1: In iBooks tap Select button on the upper right
- Step 2: Tap the circle in front of the document title to select it. Tap on the title you want to change to bring up the keyboard, and type in the new name.
- Step 3: Tap the Done button on the upper right to save the new title.
Five years ago today: Baked Kale Frittata