The process of learning about emerging technologies is continuously changing. Years ago I would spend my time in a mega magazine store (Erieview News) searching for esoteric magazines that might cover emerging technologies. Somewhere on the racks, I would usually find a technical magazine, or a magazine with a relevant column, or a stapled- together newsletter that covered whatever emerging technologies I was researching.
Even then books were not a good source for learning about emerging technologies. In fact, if there was already a formal book published it was a sign that the technology was no longer emerging but already emerged.
The current process for learning about emerging technologies involves Google searches, websites, YouTube, Reddit, Twitter, Telegram, and particularly podcasts. For some reason, podcasts have become the go-to resource for people that are fascinated with emerging technologies and are therefore a great way for us to learn about them.