It is a good practice to use underscores in place of spaces when naming files that consist of more than one word. The viewer can synchronize TOC books and pages with the topic content displayed in the right-hand pane.
If your project includes topics that use spaces with file names, you do not have to manually rename them. To save time, you can automatically rename them.
From the Tools menu, select Convert Spaces to Underscores. All topics are automatically updated.
Tip: You can automatically use underscores in place of spaces whenever you create new files. For more information, see Saving file names with underscores.