If you want The Portent in hard copy (paperback), that’s available from Amazon.
If you want the book in Amazon’s Kindle format, click here.
I’d encourage you to try the Vyrso version. Vyrso is an eBook platform created by Logos Bible Software. The Portent for Vyrso is available here.
Kindle books can be read on a Kindle Paperwhite, Kindle Fire Tablet, Fire phone, or any device with a Kindle app. The main difference with Vyrso is that Vyrso is curated in ways that appeal to their inclusion within a biblical / theological library. Vyrso books are also tagged. For reasons you might want to start reading books on the Vyrso platform, click here.