Wright states that he came to realize that he had..."somehow overlooked something very important in life." What does he mean by this statement, and why does it matter?

Wright's reading of H.L. Mencken transformed his thoughts and he realized that there was enormous power in the reading and study of literature.

The importance of this statement and the underlying realization led to Richard Wright's emancipation.  Thus, true and lasting freedom is first won in the spirit, in the inner man, or in the man's heart.

Explanation:

When Richard devised a means to borrow books from the library using his Irish friend's library card, he became fascinated with literature, and especially, the writings of H. L. Mencken.  Then, he developed much interest in general reading and the study of written materials.

These regular habit transformed his outlook in life and gingered him to conquer himself and to enjoy real freedom - freedom of thought.  This implies that literature inspired Richard Wright to escape from black oppression and suppression.

Richard Wright used his 1954 autobiography titled the "Black Boy" to expose the humanitarian crises triggered by rancorous racism, racial identity questions, and racial conflicts, especially as it affects the African American in Southern U.S.A.