Segregation
Although there is no state-mandated segregation in Chicago, where the movie takes place, one of the themes of the book is the self-imposed segregation that both the black and the white citizens of a Chicago adhere to. The main example of this is when Lena purchased a home in a currently all-white area of town. She is free to do this and there are no laws that can prevent her from doing so yet the people already residing there would prefer that their neighborhood remains segregated anyway and protest to their home owners' association about the Youngers moving in. Similarly it is shown that although many other black families like Lena's could also relocate to the predominantly white areas of the city, they choose not to, and the result of this is the continued division on racial bases despite no legal necessity for it to be so.
Greed
Walter is greedy. He is greedy for what he feels he is entitled to, greedy for success, greedy for something better than what he currently has. This greed blinds him to the needs of his mother and results in him losing a large amount of her money because he falls victim to the kind of person who promises maximum return for minimum effort. The theme of greed deals primarily with Walter and how his greed actually harms his family and himself financially.
Education As A Way Up
Beneatha has aspirations of becoming a doctor and this is her way of moving up, of getting further than her parents did. The only way she can see to better her life is through education. However there is also a degree of educational snobbery within her as she is anxious that her mother not show her up in front of her better educated friend whom she is desperate to impress. The fact that education is helping her rise in life also creates tension between Beneatha and Walter as he is jealous and feels that his mother rates education higher than ambition and that is why she has given Beneatha the remainder of the money. He is negative about his sister's prospects and makes fun of her educational aspirations.
Alcoholism
A very small sub-theme in the movie is alcoholism and shows why it is nicknamed the "demon drink". Walter has his faults but one of them is not lack of ambition and he is determined to make a success of the liquor store should he actually be able to invest in it. However, Walter also begins to drink a lot and this changes both his character and his judgement, leading to him trusting a friend whom he should never have trusted and giving him all of his money to invest. The theme of alcoholism also shows why Lena was anxious about Walter opening a liquor store in the first place and suggests that his problem might pre-date the death of his father and be something that Lena is already aware of.
Africa
Discrimination and segregation are strong themes in the movie, and the different characters seek different paths to overcome these obstacles. The character, Jospeph Asagi, represents one of the paths people took. This path is to return to Africa. Asagi brings Beneatha a dress from Africa, and he asks her to go to Nigeria with him. This path towards upward mobility rejects all forms of assimilation. Asagi criticizes Beneatha for straightening her hair as he believes this, itself, is a form of assimilation. He wants to reject the white culture that took the names of slaves as well as their freedom.
Of note, this African culture is no longer the culture of the Younger family as they have only known American culture. As a result, Beneatha would be returning to a culture that belonged to her ancestors but never to her. By including this option whereby Beneatha returns to an Africa she never knew personally, Hansberry is accomplishing two things. First, she is demonstrating a path that people did espouse at the time. Second, she is highlighting the fact that poor African American people at time were rejected by the larger American culture and were no longer a part of the African culture.
Growth
The characters in the film are all looking to improve their situation, but they have different ways of trying to achieve it.
Mama Younger wants to use her husband's inheritance to move herself, her children, and her grandson into a nicer neighborhood with a yard. She maintains this conviction even when she realizes they aren't welcome and perhaps won't be safe in their new neighborhood. Walter Younger, on the other hand, wants to buy a part in a liquor store in order to build a business and earn money for his family. His sister, Beneatha Younger, sees education as a way out, and she has dreams of becoming a doctor while her friend, Joseph Asagi, sees escape as a way up, and he wants to go to Africa.
