Publisher's This edition from 2021 is outdated and does not make use of the most recent Roblox features and Luau programming scenarios. A new second edition, updated for Roblox, Luau scripting from scratch, 2 end-to-end games, and a bonus chapter on 50 cool things to do on Roblox has now been published.
I had already been making Roblox games for ~2 years when I started reading this, but read it to make sure I hadn't missed anything that might be helpful. And actually I did pick up several small useful tips from this.
Simple things that hadn't occurred to me at all. For example if you are looking for a sound, instead of just searching for the sound by searching for sounds by name in Toolbox, you can also search for models that might contain that sound.
When testing a game, shift-P switches to free camera. That you can use instances as table keys. That a CFrame has a constructor that makes a CFrame positioned at part A and looking at part B. That when doing vector math, you can say 2 / Vector3.new(2,4,6) to get (1, 0.5, 0.333). etc. etc.
In my notes I found 50 little tips like that in this book, so it was worth reading.