These are the notes for a talk I gave at RubyKaigi 2021, which is why they’re written as if we were talking and going through some slides and code together. Hello I’m Chris Seaton. I’m a Senior Staff Engineer at Shopify where I’m working on Ruby performance. I’m the founder of TruffleRuby, which is a very highly optimizing implementation of Ruby. I also maintain The Ruby Bibliography at rubybib.or