Given the limited space, I will have to deal briefly with what is a big question. To begin with, there are five major characters in Chimamanda Ngozi Adichie's debut novel, Purple Hibiscus, first published in 2003. There is a family of four: father (Eugene), mother (Beatrice), daughter (Kambili), and son (Jaja), who live prosperously in postcolonial Nigeria, and the children's aunt, Ifeoma, who lives in a smaller, shabbier village. The family is Catholic and dominated by the father, who is a successful businessman that believes strongly in his religion and frequently resorts to violence, at one point putting Kambili in the hospital.
Kambili is a self-conscious teenage girl who narrates the novel, while her brother is a little more independent and defiant, although he too is a victim of their father's violence. Their aunt, while still religious, teaches at a university and is far more free-spirited, open, and kind than Eugene, her brother. There are significant supporting characters, like the priests and the children's grandfather, but there isn't space to discuss them.
Thematically, the novel, like much contemporary African literature, deals with the colonial past and its aftereffects. The English colonized the country in the 19th century, and their influence still lingers, notably in the form of Catholicism. Nigerian novelists, of which Adichie is foremost, are often wrestling with the tension between past and present, between their colonial history and their older, pre-colonial history—much of which was eradicated. Eugene and Ifeoma's father, for example, is not Catholic and is more traditional and in touch with the old ways. While he is a link to a deeper, non-Western past, Eugene frequently belittles his beliefs and rituals as "heathen" or "pagan." A final theme worth noting is that of maturity; i.e., this is a coming-of-age tale or, as the Germans call it, a bildungsroman.