What’s a short non-fiction that is a must read

I’m getting back into reading but I’m backlogged with a big ole book that’s a bit daunting (Stalingrad – Vasily Grossman)

In the meantime, I want to stay motivated to keep reading with some shorter non-fiction. They can be history, philosophy, finance, biographies, science, self-improvement, etc. I just want to learn about interesting topics or insightful knowledge while I’m tackling a bigger fiction work