Once you've created a series of font collections, it'll be necessary to instruct the Font Book application () as to what fonts you want to use, and what fonts you want to turn off. It's important to understand that fonts consume memory on your computer. For example, if you have hundreds of fonts active (and that's not unusual), it takes more RAM memory to maintain those fonts; even if you're not using them. That's where font management comes into play. Using Font Book, you can decide what fonts you need, and what fonts can be retired, or disabled, for the remainder of the work session.
Activate and Deactivate Fonts
Open the Applications folder, and then double-click the Font Book icon.
To activate all the fonts in the Collection, select a Collection, and then click the Enable button.
To activate selected fonts, select one of more fonts from the Font column, and then click Enable.
If a font is disabled, it says Off to the right of the font.
To deactivate a collection or a font, select the collection or font, and then click Disable.
IMPORTANTThe Enable button is a toggle, when a font is active, it displays the word Disable, and when a font is disabled it displays the word Enable.