I very much love Tadge Dryja's lectures
https://ocw.mit.edu/courses/mas-s62-cryptocurrency-engineering-and-design-spring-2018/video_galleries/lecture-videos/

But you learn the most by building things. Also, toying around with building your own bitcoin library is a great way to learn about how things work under the hood 

robin_linus

What's your approach to learning? What would you advise to somebody starting from scratch that wants to contribute to projects like the ones you've worked on?