If you open the Navigation Pane in MS Word, e.g. with Ctrl+F in order to search for something in your document, sometimes you cannot close it using the Esc key, and you need to grab the mouse in order to aim this little x at the right top corner.

You can avoid this trouble by pressing (one after another, not all together) alt, then w, then k. This sequence is a toggle key, it lets you close the Navigation Pane, but if it is closed, it will open it.

Other useful Navigation Pane shortcuts include:

F6 / Shift+F6 — When the Navigation Pane is open, to switch forward / backwards between (1) Navigation Pane, (2) Bottom Taskbar, (3) Ribbon, and (4) Document

Tab / Shift+Tab — In the Navigation Pane, to move through the pane’s options

Being yourself an author or student you will perhaps appreciate especially this feature, that the very structure of the book will teach you how to work. The book contains even chapters on how to prepare a document for professional publishers such as Amazon. Reading Steven Adams' Writing a book or thesis in Microsoft Word you are surprised realizing it makes you want to work -- to think, write, use Word and be creative!