The subject of the present volume, in essence is the hand and hand's extensions. We cannot insist too strongly that in the evolution of life the "decisive moment" arrived when a living being – who became man – adopted the erect attitude, thus freeing his hands, and when the industrious activity was inauguarted which this freedom made possible. In the use of the hand as an instrument, we have the manifestation of an important physical progress and the promise of further progress.
