Sentence:  These sages include poet Carl Sandburg , statesman Jawaharlal Nehru and sculptor Jacques Lipchitz , in Volume <WSD>One</WSD> , and playwright Sean O'Casey , David Ben-Gurion , philosopher Bertrand Russell and the late Frank Lloyd Wright in the second set . 
Meaning of the word marked with <WSD> tags:  having the indivisible character of a unit