r/MachineLearning - [D] What is the path to getting a *deep* understanding of machine learning. Deep enough that if you were in one of the top AI labs in the country (Google Brain, Deep Mind, Facebook AI, etc.) you would be able to keep up with your peers? Reading list?

Many of those researchers will have PhDs and long CVs full of peer-reviewed research articles. ML engineering is often the applied side of the (more theoretical) research that began in theirs and their peers' minds. I would recommend identifying pathways for collaborating with established ML researchers on published (and refereed) research papers. Another major difference between an ML engineer and an ML researcher to keep in mind is that the ML researchers at major companies and universities are world-class experts in their respective very very narrow subfields. Some of them will have invented the entire topic that they're an expert in.