Prominent Americans series

This was the first U. S. omnibus definitive series in which Benjamin Franklin did not appear on one of the lower-valued issues.

The values of the new series included figures from all walks of life, each depicted in a different style by a different designer, presumably in a quest for wider diversity—a significant departure from the uniformity of concept that had marked previous definitive issues.

That portraits of two women appear in the series (Elizabeth Blackwell and Lucy Stone) represented a small but significant step toward gender equality in U. S. Stamp history: no previous definitive set had included more than one prominent female (Martha Washington in the issues of 1902, 1922 and 1938; Susan B. Anthony in the Liberty series).

This was also the first definitive issue to include a stamp devoted to an African-American, with Frederick Douglass portrayed on the 25¢ denomination.

[1][2] The $1 Eugene O'Neill stamp was notable for its repeated use by Theodore Kaczynski, the Unabomber, who habitually used them on his mail bombs.