PRIOR to this, no complete, authentic, and authorized record of the work of Mr. Edison, during an active life, has been given to the world. That life, if there is anything in heredity, is very far from finished; and while it continues there will be new achievement. An insistently expressed desire on the part of the public for a definitive biography of Edison was the reason for the following pages. The present authors deem themselves happy in the confidence reposed in them, and in the constant assistance they have enjoyed from Mr. Edison while preparing these pages, a great many of which are altogether his own