The biggest complaint students make about Mockingbird has to do with the first chapter. It is complex and difficult to follow because Lee jumps back and forth from the Finch's past to the present ways of Maycomb without providing clear transitions. By the end of the chapter, the reader has an exhorbitant amount of background information on so many characters that it is hard to keep them all straight. Because no action has taken place thus far, there is no plot line for the reader to follow, thus he is unsure about what information is pertinant and what is of peripheral importance. Digesting all the information in the first chapter is difficult even for an advance reader.
Another common criticism of the novel is its lack of cohesiveness. There are two plot lines in the book. Lee spends a lot of time concentrating on Boo Radley early in the book, then abandons that story line for the Tom Robinson saga. It is only in the end that Lee weaves the two together. In addition, each chapter often reads like its own separate short story rather than a continuous book. For example, the chapter of Atticus shooting the dog does provide a greater insight into Atticus' complex character, but could be left out as it is an aside of the story's development. The same could be said about the chapter about Scout's experience with Francis at Finch Landing.