Grin council member Jasper van der Maarel gave this excellent presentation on Mimblewimble and Grin at Bitcoin Wednesday on 5 December, 2018. It’s a very strong introduction to the technology behind the anonymous-by-default cryptocurrency protocol.
This talk was held at Circl, the Sustainability Pavilion at ABN Amro Bank’s Amsterdam headquarters. He also gave this interview right before the event.
You can read his profile here, and you can also find an overview of the complete program for that evening.