Based on the context and the answer, generate a question. 

Context: I finished PROBLEM OF THE CENTURY : RACIAL STRATIFICATION IN THE UNITED STATES today on my walk to work . It was the final book I had checked out for my Race / Ethnicity class , but I had n't needed it for the coursework . I decided to read it anyways before returning it , and to be honest , it was difficult to stay focused and read it thoroughly . The difficulty was n't motivation ( or at least not primarily ) .

Answer:

Racial issues .



What subject does the narrator like to study ?