The wheel

"In this book, Richard W. Bulliet focuses on three major phases in the evolution of the wheel and their relationship to the needs and ambitions of human society. He begins in 4000 B.C.E. with the first wheels affixed to axles. He then follows with the innovation of wheels turning independently on their axles and concludes five thousand years later with the caster, a single rotating and pivoting wheel. Bulliet's most interesting finding is that a simple desire to move things from place to place did not drive the wheel's development. If that were the case, the wheel could have been invented at…