I think this is a great book IF you’re a scientist (like me!). Like the other reviews say, it is a little dated – but results are results. There is a wealth of info in this book, most of it is technical, and there is some fascinating things on human powered flight & HPVs. I can’t remember the exact figure that was quoted for the weights of some of the older historical bikes, but I find it hard to believe that there were such lightweights a hundred years ago (like 6kg). Knowing what I know, I just don’t think it would have been feasible. If you are interested, I wouldn’t wait for an updated edition, because they might not make it, and this one is getting pretty darn hard to get.