Back when deep learning didn't have a fancy name yet, it was called artificial neural networks. So you already know a great deal about it!
Eventually, interest in neural networks was rekindled in 1986 when David Rumelhart, Geoffrey Hinton, and Ronald Williams were involved in the (re)discovery and popularization of the aforementioned backpropagation algorithm. However, it was not until recently that computers became powerful enough so they could actually execute the backpropagation algorithm on large-scale networks, leading to a surge in deep learning research.
You can find more information on the history and origin of deep learning in the following scientific article: Wang and Raj (2017), On the Origin of Deep Learning, arXiv:1702.07800.
With the current popularity of deep learning in both industry and academia, we are fortunate enough...