I already have the Arms & Equipment Guide ($26.95), Arms & Armor ($25), and the Ultimate Equipment Guide ($34.95), so I just can't see justifying spending the $39.95 on From Stone To Steel. The other books barely get enough use IMC to make their investment worthwhile, and I don't see this item doing even as well as those for my group.
It's not only a case of coming to the table too late (long after everybody else's books came out) but the huge price tag and the limited usefulness of most of the material to me. I don't play Stone Age, Native American, African, Bronze Age or whatever time period, so most of the book is completely useless to me. That, and there is no other equipmenmt listed, makes for a big minus IMO. Additionally, the interior art doesn't get me excited to use any of the items depicted; it's serviceable, but nothing to write home about. I was bored flipping through it; nothing caught my eye, unlike the other books mentioned (which all have their shortcomings--some more than others--so don't get me wrong).
From Stone To Steel is okay, but not something I'd ever consider spending $40 on unless I didn't have the other books mentioned or had a special need for items for other time periods beyond the standard medieval. I'm glad the book is available for those who want its specialized material, but again, it's not something I see most gamers needing as a "must have" book, contrary to what some other posters are loudly proclaiming in this thread. Not only that, but this thread needed a divergent opinion other than "It's amazing!"

I'm gonna level up in Devil's Advocate now, I think.
PS: I also didn't think Nyambe or Occult Lore were "must haves" and don't own either. I had no interest in Nyambe's setting (not that it isn't well-written), and was not impressed with Occult Lore in the least. The only "must have" books are the three core rule books, LOL. Everything else is going to be hit or miss depending on the needs and interests of the individual gamer. One person's trash is another's treasure, as the old saying goes.
