What is the general topic (theme) of The Color of Water?

I assume by "topic" you mean theme--in other words, what
is the primary message or focus of this book. The Color of Water by
James McBride is one man's journey to discover how, exactly, he fits into this world. He
is in search of his cultural identity. This is something most people kind of already
know or can generally figure out; however, James has many elements of his life which are
confusing to him until he is able to uncover his mother's life
story.

James grows up in the projects of New York, and his
identity as a black person is fairly well defined by the men in his life. His father was
a black man and so was his stepfather. There is no ambiguity to them. When it comes to
his mother, though, there are so many ambiguities and she flatly refusesto talk about
any of them with her children. It is James's nature that he needs to know her story in
order to make sense of his own.

First, she is not black but
presents herself as such in the way she talks, the way she behaves, and where she lives.
Despite being white, she clearly identifies herself with black women in ways that can be
seen. On the other hand, Ruth acts against the black stereotype by
insisting her children go to the best schools she can manage for them--almost always
white, and often Jewish. This does not fit with who Ruth appears to
be.

Second, Ruth is Jewish but raises her children as
protestants; her Jewishness is one of the ambiguities about her that James finds
unsettling. Third, she values family above all things and is adamant that her children
never speak about family matters outside of the family; yet, ironically, she never
speaks at all about her own family or about her time before marrying James's
dad.

All of these ambiguities are a consistent undercurrent
in James's life, and he is one of Ruth's only children to "act out" because of it. As he
finally gets his mother to speak to him, James is able to put the pieces together and
make some sense of his instincts and intuitions. Once he knows from where his mother
came, her rather odd behaviors make more sense to him and in turn help him make sense of
his own life.

All of these things are disconcerting to
James as he tries to understand his heritage; once his mother tells him the truths of
her life, James is able at last to reconcile his feelings with his
experiences.