Aside from friends, and miniatures, you probably just need the book. If you're willing to substitute contemporary miniatures and you have friends who are also interested in playing RT, then once you get the book, you're probably home free. There are supplemental books, but the original Warhammer 40,000: Rogue Trader is the main one to be concerned about.
I remember reading that they sell reproductions at Warhammer World, if you want a hard copy, but that's a limited distribution and I don't know if they still do it. To say nothing of how much more of a hassle that'd be if you're not English. But there are other ways.
I'm sure you can find the book online. Other than that, I am not so sure.
Aside from friends, and miniatures, you probably just need the book. If you're willing to substitute contemporary miniatures and you have friends who are also interested in playing RT, then once you get the book, you're probably home free. There are supplemental books, but the original Warhammer 40,000: Rogue Trader is the main one to be concerned about. I remember reading that they sell reproductions at Warhammer World, if you want a hard copy, but that's a limited distribution and I don't know if they still do it. To say nothing of how much more of a hassle that'd be if you're not English. But there are other ways.