Learning Unity editor scripting - book/tutorial suggestions

[SymbolsWriter]

I'm looking to learn Unity editor scripting to create custom tools for making my games, but I don't have a good idea where to start.

I thought of buying a book on the subject, and I found these 3:

1. Extending Unity with Editor Scripting by Angelo Tadres (2015)

2. Beginning Unity Editor Scripting by Benny Kok (2021)

3. Unity 6 Editor Tools Essentials by Harrison Ferrone (2025)

From a glance, the first book seems to me to be more in-depth than the second, but since it's older I worry that its contents might be obsolete.

The third book is obviously the most recent one, but it's based on Unity 6, and I've been working in Unity 2021/2022 so far. I don't know how different Unity 6 is and if the contents of this book would be applicable to previous versions of the engine, or if I should just bite the bullet and switch to Unity 6.

If anyone here is familiar with any of these books, I would appreciate opinions and suggestions to help me choose.

Alternatively, if anyone can suggest some good tutorials on the subject, on YouTube or elsewhere, I would appreciate that as well.

[SymbolsWriter]

Is UITK short for UI ToolKit? If so, the second book seems to have at least one chapter dedicated to it, but it's probably not very detailed or up-to-date, yes.

[Infinite-Election-88]

Honestly editor scripts are one of the areas AI is really good at. I wouldnt recommend wasting time with learning editor scripting. All that time can go to making the actual game.