Steve Fenton is a Principal DevEx Researcher at Octopus Deploy, a DORA Community Guide, and a seven-time Microsoft MVP for developer technologies. He’s a Software Punk, an author, a programming-architect, a pragmatist/abstractionist, and a generalising-generalist. He has written books on TypeScript, Octopus Deploy, and Web Operations Monitoring.
A nice and short introduction to TypeScript. It's article length rather than book (that's why it's called a mini book). it's enough to get you started but there's much more into the language, so it's expected to be used as stepping stone to more detailed books or a crash course to get you started. not to be used as a reference.