In Up from Slavery, what did Booker T. Washington consider the cause of the race problem?

In this book, as in his entire life, Washington felt that
the most important thing for black people was to be educated and hard-working.  The
education that he felt was important was mostly vocational education that would allow
blacks to be good workers.  From this, we can infer that Washington felt that the cause
of the race problem was the fact that blacks were insufficiently trained and
insufficiently industrious.

To Washington, the only real
solution to the race problem was hard work.  He wanted blacks to "cast down their
buckets" where they were.  He wanted them to accept that their place (at that point in
history) was to do the hard work of agriculture and mining and domestic service.  He
felt that blacks who were properly educated and properly hard-working would win the
respect of whites.

Washington does not explicitly say what
he thinks the cause of the race problem is.  But we can infer it from what he encourages
blacks to do.  He clearly feels that the cause of the problem is that whites do not
respect blacks and that this lack of respect comes from blacks' lack of education and
industriousness.