First thing’s first, a call to action is a marketing term for a design that prompts the viewer to an immediate action. For example, when you go on a website and they ask for your email. That is what we are looking for!
People need to be reminded, it’s as simple as that. Having a call to action on your website prompting the viewer to put in an email so they can stay up to date is a genius tactic. If you already have one- great! Just make sure you use it.
Your call to action can simply ask for an email, but you might want to think of an incentive to do so, such as receiving an exclusive monthly newsletter. Regardless, you should use this to give your readers notifications about upcoming books, or any highlights you have going on.