Who was madam cj walker?

Madam C.J. Walker (December 23, 1867 - May 25, 1919) was an African-American businesswoman,hair care entrepreneur and philanthropist. She made her fortune by developing and marketing a hugely successful line of beauty and hair products for black women, under the company she founded, Madam C.J. Walker Manufacturing Company.
The Guinness Book of Records cites Walker as the first female who became a millionaire by her own achievements.
Source: On Her Own Ground: The Life and Times of Madam C. J. Walker (Scribner 2001) by A'Lelia Bundles