It is essential to realise that Dickens carefully structured this excellent story by dividing it into three distinct stages. These actually relate to the three volumes of the first edition when this novel first was published, but even though we do not have this novel divided up now, it is still important to consider the structure and how and why it is divided into three books. Critics have debated the structure of these three books hotly, and the following conclusions they have come to are as follows.
One interpretation is that the books represent the three Christian stages of innocence (Pip's childhood), fall and sin (his "Great Expectations") and then finally redemption through suffering (the ending). Dickens was a writer whose Christian beliefs impacted his work greatly, and we can trace certain key Christian motifs through his journey, in particular the concept of losing his world and his riches to gain his soul. An argument that backs up this Christian interpretation of the structure of this novel is the number of Biblical references that are used at key points in the novel, such as in Chapter 19 when Pip discovers his expectations. There is also a very telling allusion at the very end of Chapter 19 from Paradise Lost, when Pip leaves his home and says, "the world lay spread before me," comparing his departure from his home and the marshes to the expulsion of Adam and Eve from the Garden of Eden.
A second interpretation involves looking at this classic as a kind of moral fable, commenting harshly on a newly affluent society with many people suddenly finding they have great expectations. Such an approach would therefore focus on the dangers and possibilities of such a change in circumstance. This might focus on the moral development of Pip. He is removed from his roots, goes to a city that is consumed by commercialism where he receives an education. When tragedy occurs, he realises that he can never return to his simple origins, but, a much maturer and sadder individual, he can prosper as a businessman by using his own talents rather than living off the corrupt money of others. This view would tie in very closely to Pip's own growing sense and understanding of his own character and motives.