With the Book Creator 5.0 update, we added the option to preview and read your book within Book Creator.
Reading your book
In the toolbar, you'll see a new Play button. When you're ready to read your book, tap on this to switch from the editor mode to the preview mode.
You'll know you're in the Reading mode if you see the app background changes to blue, and the toolbar changes to have the new options.
Read to me with Siri
If you tap the Read to me button in the toolbar Siri will automatically start reading the page. Words will be highlighted as they are read.
There are a number of settings you can change for how the reading mode works. Tap the Settings icon in the toolbar.
Display - toggle between side by side pages or single page view.
Voice - Choose the language you would like Siri to read in. Some languages have more than one reading voice option, and you can also download more voices.
Highlight words - Toggle on/off.
Play multimedia - Toggle on/off whether or not to play and audio hotspots or embedded video whilst reading.
Turn pages automatically - Toggle on/off. Siri will turn the pages automatically by default, if you want to do this yourself, turn this setting off, then turn the pages by swiping or tapping the edge of the page.
Slow speech rate - If you want to slow down the speed at which Siri reads, toggle this on.
From the blog: