You can run a BookBub Ads campaign for any book at any time. When you create a campaign, you decide which readers you want to target and how much you’d like to bid to reach those readers. These bids compete in an auction that determines when and which ads are displayed to our readers. When a reader opens an email from BookBub or a page on BookBub.com, our platform displays the highest-bidding ad targeting that reader at that moment.