mchnhd4 - you need to capture the contacts. Get them in your funnel so you can remarket to them. Most people don't buy/engage until the 7th contact (this is in the marketing field, real estate may be different).
To capture emails, you need an autorepsonder and landing page creator. The landing page allows you to get their email in exchange for the book. The autoresponder allows you to send follow up emails to them.
There are plenty of each out there. Most these days integrate with each other. Just get the one that fits your budget. You don't need to spend a fortune. I don't promote any of them, but I have used GetResponse, and they had a landing page creator integrated into it for an extra fee...
Hope that helps and let me know if you have any other questions.
Brad (reformed marketer)