Legendary Crafting Question
You should be able to start at 1 but you will need 4 to finish. You can just check with the vendor if he will see you the book to unlock the collection. Pretty sure I bought the book and unlocked the collection before getting the fourth mastery.
I have the first book and unlocked it. I just wish I had NOT spent my Tyrian Mastery points on other things. Chalk it up to being a noob. Guess it’s time to get more Tyrian Mastery Points.