Final answer:
W.E.B. Du Bois, a noteworthy civil rights activist and NAACP co-founder, was honored as the 19th figure in the Black History Heritage Stamp Series on February 1, 1996.
Step-by-step explanation:
The individual honored as the 19th honoree in the U.S. Postal Service's Black History Heritage Stamp Series on February 1, 1996, was W.E.B. Du Bois.
He was a prominent African American civil rights activist, historian, and one of the founding members of the National Association for the Advancement of Colored People (NAACP). W.E.B. Du Bois's contributions to American society and the civil rights movement were significant, and the stamp release was a part of the effort by the Postal Service to commemorate figures who have had a remarkable impact on Black history and culture. Earlier, the Postal Service had also commemorated other individuals, such as Salem Poor for his participation in the American Revolution, through the Gallant Soldier series in 1975.
These stamps serve not only as a form of postal currency but also as a powerful tool for education and recognition of the integral roles African Americans have played in shaping American history.