The crucial message of this book is shown through the way in which Jeffery lives and intereacts with a series of different characters who are all to some extent divided by racism. What he does through being the only character to freely interact with both blacks and whites is to make others realise that actually, these two different groups of people are not that different from each other and that both are human. Maniac Magee manages to somehow draw love out of all characters in a very antagonistic situation to let both groups see the humanity in the other group and vice versa. Let us remember the kind of setting that this story is based in:
Hector Street was the boundary between East and West Ends. Or, to put it another way, between the blcks and whites. Not that you never saw a white in the East End or a black in the West End. People did cross the line now and then, especially if they were adults, and it was daylight.
The community where Maniac lives is segregated. However, gradually, what we see during the course of the novel, is that some of the barriers separating these two groups are broken down thanks to Maniac Magee.