Audubon's life naturally divides itself into three periods: his youth, which was on the whole a gay and happy one, and which lasted till the time of his marriage at the age of twenty-eight; his business career which followed, lasting ten or more years, and consisting mainly in getting rid of the fortune his father had left him; and his career as an ornithologist which, though attended with great hardships and privations, brought him much happiness and, long before the end, substantial pecuniary rewards. (Summary from the Preface)