This error was occurring intermittently when I began. However, I just placed a small cogwheel to power a mill and now I can't open my world without this crash.

The root of the error says error while loading contents for book thermal:guidebook. But here is the entire log below.

Thank you

latest.log

This looks a lot like corrupted mods causing inter-dependency problems. Try downloading the pack again. What launcher do you use?

Unfortunately you may have lost any progress you made, but you can try to explicitly download to a new instance and copy your saved data. Can't guarantee that will work.

I had the same issue.

Reinstalling modpack and removing Optifine did help.