can i import the titles of photos into a book?

That theme are you using? Some themes have a text field for the Title that gets populated automatically. Does your theme have such a text field.

The one theme that I know has that is Folio.

Otherwise Command (right) - click on each photo on the page and select Edit from the contextual menu. In the edit mode the file title will be displayed at the top of the Edit window. You can copy it, exit the Edit mode and paste it in the text box as needed. Not a very elegant workflow but will work.

Happy Holidays