The book is an adaptation of essays she wrote for O, the Oprah Magazine for the past 14 years, reported Ace Showbiz.
'What I Know For Sure' marks publishing house Flatiron Books' first release.
"The essays offer a rare, powerful, and intimate glimpse into Oprah's inner life - her thoughts, struggles, and dreams - while providing readers a guide to becoming their best selves," the publisher said.
"Candid, moving, exhilarating, uplifting, and frequently humorous, the words Oprah shares in 'What I Know For Sure' shimmer with the sort of truth that readers will turn to again and again," the publisher added.