Hit the [ \ ] key
Thanks, but it didn't work
Works fine here: [ \ ] shows and hides the header bar in the work area. The button should appear to the immediate left of the Book Settings panel.
If you hit the [ \ ] key does anything happen?
The \ key will hide and show the header bar in the book module and the Create Saved Book button is at the right of that header bar.
The outlined area is what shows and hides when the \ key is pressed. Maybe you have a keyboard that has a different key for \? On my keyboard the \ key is just above the Enter key.
You can also use the View / Show Header Bar in the LR menus across the top:
If this doesn't work, then can you provide a screenshot of your LR book module?
Note: If you've previously saved the book upon which you are working you will not get the Save Book button again. It will autosave as each change is made. Is it possible you've saved this previously? It is easy to tell as you will have the words Unsaved Book on the left side of the Header Bar. If the book has been saved previously it will say only the book title.
The \ key does hide/show the header bar, but no create save book button. I must have inadvertently saved it in some fashion, but I could not find the little icon that indicates a saved book. Since this dialog started, in my frustration, saved it in a collection. Before and after that, I never saw "unsaved book".
Thanks to all, I'll do another book soon and monitor the header bar more closely.