When we think about the Stone Age, we think of cave men, or The Flintstones. You might be surprised at the many important steps that mankind took toward civilization during the Stone Age, which lasted a couple of million years. What we think of as "primitive" during that period was the best life ever gets for early man, and those folks made great efforts toward making their own lives better with new ideas and technical innovations. We call it the Stone Age because that's what they left behind. Who knows what else they used? Bones, sure, and maybe wood, leather, plants, and a host of other things that just didn't survive long enough for us to find them. Meanwhile, humans developed fire-making, cooking, art, clothing, agriculture, and long-distance travel. That's a lot of innovation for "cave men." We only call them "prehistoric" because they didn't write their accomplishments down, but we can figure out their history from what little they did leave behind.