For one of the sites, I had created a huge book with lot of pages , child pages. Now I wanted to display that as menu. It was really tough, as I did not find any writeup for the same. I found the solution and thought of sharing with my readers. I wanted to place the Top page of the book as one of the menu in the Main menu of my drupal Site. And on mouse over all child pages should be displayed. I search in the basic configuration and did not find any way to do this. This is how to proceed.
First Make Book as Menu.
What it means is your first page of the book should be the top menu and all pages of the book should be displayed as child menu or menu items. You will have to goto your drupal database, Goto menu table, here you will find an entry starting with "book-toc-xx", xx is a number in my case it was "book-toc-88'. Copy this entry.
Goto menu_custom table and INSERT a new entry with "book-toc-88" and save.
Now goto your drupal site and Run the database updates and CRON. When you goto Structure >> Menus , you should now see the new Menu with the Name you have entered in Database.
After you have done this, you should see the new menu .
Step 2 - Goto the first page of your book in the Menu item (//admin/structure/menu >> Pick your newly created Book Menu >> List Links >> Then Click Edit on the first page of your Book ), Here Change the Parent item to Primary menu or Main Menu. You should now see the Book as part of your menu.
Step 3 - Install Superfish contributed module. Create a new block and place the menu in the header which will replace the original menu.
If you have done this correctly , you now have a drop down menu with your Drupal Book.
Other options in case you dont want to insert Book in the main menu.
Install Nice Menus module and in configuration page add 1 Block
When you goto the Block settings you will find this BOOK MENU and you will be able to make this into a Block with Navigation on Mouse hover.
You can install jquery menu module https://drupal.org/project/jquerymenu
. In settings page of jquery menu, select the newly add BOOK MENU. Goto Block page and add the block to one of your regions. When you display the book Navigation , you will see + sign for items where there are child pages. However I did not like this option as + sign is not very User friendly.