E.R. Braithwaite's To Sir With Love details issues of race, class, and education; it is essentially an account of how a black man navigates his life within a social construct which often marginalizes his efforts to achieve significance.
It appears that Braithwaite wrote the book not only to delineate the entrenched prejudices he encountered within English society, but also to highlight what he felt was the best way to respond to such discrimination:
I made it clear that … colored people in England were gradually working for their own salvation, realizing that it was not enough for them to complain about injustices done to them, or rely on interested parties to agitate on their behalf. They were working to show their worth, integrity and dignity in spite of the forces opposed to them.
In his book, Braithwaite manages to maintain a spell-binding authenticity which blends his humanity ( his irritation, anger, and disgust) with his idealism (his desire to rise above the bigotry and preconceived notions of English society). This example is evident in his decision to teach. An educated black man, Braithwaite holds a post-graduate degree in physics from Cambridge University; understandably, his disappointment is palpable when he is repeatedly turned down for gainful employment:
"I had just been brought face to face with something I had either forgotten or completely ignored for more than six exciting years - my black skin ... Disappointment and resentment were a solid bitter rising lump inside me; I hurried into the nearest public lavatory and was violently sick."
Having never encountered prejudice during his time in academia or the British Armed Forces, Braithwaite is unprepared for the exclusiveness of mainstream English society. Even his impoverished white students are not above displaying the same narrow attitudes typical of the wealthier classes. If his students are less than impressed with Braithwaite, the scientist turned teacher is just as disillusioned with his charges.
"They reminded me somehow of the peasants in a book by Steinbeck: they were of the city, but they dressed like peasants, they looked like peasants, and they talked like peasants."
So, you can see that Braithwaite's honesty lends the novel an air of authenticity. This may have been his purpose; Braithwaite's raw portrayals of mainstream English prejudices and his own subsequent responses to them further illuminates the challenges that impede mutual understanding and respect in a multi-racial society.
In teaching his students to dispel deeply held prejudices, Braithwaite himself learns tolerance and understanding. His book highlights the necessity of such mutual learning and discovery as tools against prevailing challenges in race relations for present-day England.
He wanted to write this because the world thinks black people aren't important.