Harper Lee's first few pages of To Kill a Mocking Bird create mystery and intrigue. It isn't until after the first few pages that we begin to learn what is actually happening in the story. The first page is much like the first few chapters, they don't seem to be going anywhere.
Scout's voice seems to change from an innocent child's to a more mature adult quite often. This indicates that Scout is looking back at some points of the book and at other times, is talking as it happens. This shows that time has passed since Jem's broken arm. This seems to re-occur during the book as Scout seems to start talking about a time years before the book is set in the middle of something in the present.
The mentions of Boo Radley immediately build conflict between the Radleys and Jem, Scout and Dill. Boo is introduced as some loner living in his house who the children have crazy ideas about.
This shows the innocence of the children and that they are not unlike other children of their time who have an opinion on someone that may be completely off the mark.
Mystery is created in relation to the Radleys and who some of the characters are. This immediately addicts you to the book as you slowly discover the answers to thesej mysteries. This is the key element in a good book, if you can make the reader want to learn more about the people in the book, then they will read past the first chapter.
But above all, the first few pages are an introduction of the characters, themes and the location of the story. In the first page alone we discover, the names and ages of the characters, their interests (American Football), the location (USA)...