Can you go straight to this book or do you need to get a certain comfort level with f# first? I have the latest edition for F# 4 but haven't read it yet, plan to as part of my learning the language but haven't figured out order.

It's pretty good.

I certainly looked at the cheat sheets, played around a lot, read lots of online tutorials. Only once I had a basic understanding did I read Don's Expert F#, its great, but not for beginners.