This month's Puzzler

On January 6, 1883, this man was born in Bsharri, Mount Lebanon (then a part of the Ottoman Empire). He grew up in poverty, an unfortunate situation exacerbated by his father's serious gambling problems. When he was twelve, his mother decided to leave her husband and, with three children in tow, follow her brother to the United States.

While being registered in the Boston public school system, his first name was inadvertently misspelled (the letters "ha" were inadvertently transposed to "ah"). By all indications, he accepted the error, for it ultimately become the accepted spelling on all of his later published works. He lived in Boston for three years before returning to Lebanon at age fifteen to deepen his connection to his cultural heritage as he furthered his education.

In 1902, at age nineteen he returned to Boston to continue his studies and advance his career as an artist. Over the next decade, while living in Boston, Paris, and finally in New York City, he became an accomplished artist (especially skilled at portraiture, his subjects included William Butler Yeats and Carl Jung). When Auguste Rodin wanted an official portrait done, he commissioned this week's Mystery Man to do the work.

In addition to his talent as an artist, he was also a gifted writer, noted for a lyrical, poetic style and a reflective, philosophical bent. While he wrote a number of books, he is chiefly remembered for one -- a 1923 literary classic that became one of the best-selling books of all time.

Who is this man?  What was the title of the 1923 book?  (Answers below)