To spoil a little, this book considers a group of low-income whites and a group of low-income blacks.
As teenagers the whites have a pessimistic attitude about success but the blacks are more optimistic. Barriers to the success of both groups are looming.
The first edition of the book stops there: one is left with the feeling that the plight of the two groups is not that different (e.g. "systemic racism" is a real thing but doesn't seem salient when you are know "white people with black problems") Somehow, however, the blacks believe that "they can overcome".
In a follow-up study a decade later both groups are doing poorly, but the blacks in particular have had their hopes dashed by poverty, problems with the law, problems with work, etc.