A young woman is returning home to Maycomb, Alabama, from New York. It is her fifth annual trip. This time she is travelling by train, instead of by air. Her most recent flight had been a disconcerting experience, the pilot having “elected to fly through a tornado”.

There is another reason, her father is 72, and it is a 100-mile drive to Mobile. He would have to rise at 3am and then also face a full day’s work. Jean Louise Finch gazes out across the landscape, “grinned when she saw her first TV antenna atop an unpainted Negro house” – this is the 1950s – and becomes further pleased to see the increasing number of TV antennas on the homes of the black population and considers her life, not so much as it is in the present but as it has been shaped by memory.

From the opening paragraph of Go Set a Watchman, Harper Lee sets out to make her central character, Jean Louise Finch, concerned and independent, even brash, a Southern woman who has moved beyond the acceptable expectations of her social class and announces to her aunt: "I've come home for two weeks of just sitting, pure and simple...I beat my brains out all year round."

A train journey is a traditional way of beginning a story; it consolidates the idea of a narrative as a journey, not only for the writer, but also for the reader. The train also symbolises the gradual if emphatic passage towards a realisation of how life really does evolve and of the many compromises living requires.

In this her first submitted manuscript, Harper Lee was not only embarking on something bold – a female Southern writer tackling racism in 1950s America through a female character shouting at an aged father she now considers a racist hypocrite – she was unintentionally laying the foundation for her first published work, To Kill a Mockingbird, which this initial version, written in the third person, would become, two-rewrites later, on publication in 1960.

It gave the world Atticus Finch, a wise man who said: “Before I can live with other folks, I’ve got to live with myself”. In one of the most memorable moments in literature he says: “If you can learn a simple truth, Scout, you’ll get along a lot better with other folks. You never really understand a person until you consider things from his point of view.”

There are a couple of ways of reading Go Set a Watchman. In its own right it is a barely plotted novel in which an opinionated young woman, Emma-like, abruptly grasps a belated understanding of her world, most emphatically through her changed view of the father she once idolised.

Lee’s approach is earnest and wholehearted, if predictably structured and executed. It is heavy-handed and sketchy, lacking any defining set piece, with the exception of the sequence in which Jean Louise rails at her father. There is a great deal of talking; from romantic banter to polemical argument. Readers new to Lee will be experiencing a wordy first novel which is unmistakably of its time, the late 1950s – as is its language, with plentiful mentions of “Negros” and “niggers”.

Everyone else, probably the majority, as readers of To Kill a Mockingbird, will be in a more difficult position as that beloved classic stalks the pages of Go Set A Watchman. The only way to deal with the lovable spectre of Mockingbird is to bid it hush, and be quiet for as long as it takes to read its – to use Lee’s phrase – “parent” work. Only that is not so easy; little Scout Finch is a persistent individual and far more appealing than her righteous grown self, Jean Louise, now 26 and no longer a convincing tomboy with inner thoughts being filtered through a fluctuating viewpoint.

The Atticus Finch of To Kill a Mockingbird is one of the most attractive figures in literature. Here though he is older, and a racist – this will prove the toughest obstacle for most readers. The prose also shifts, from blunt realism to a more literary style.

Reading this book is one thing, reviewing it is different – Harper Lee is still alive and aware of its publication some 57 years after it was rejected, but she did not work on the final edit, stipulating that it was not to be edited.

Be absolutely clear, this is not a prequel, although it has been presented as one; it is the first version and very much a first version and there is no Boo Radley to inject an element of mystery.

The court case in which Atticus Finch defends Tom Robinson, the black man accused to raping a white woman, is the heart of To Kill a Mockingbird, as is Gregory Peck’s Oscar-winning performance the consolidation of the novel’s immortality. Yet in Go Set a Watchman, the court case is reduced to a passing reference of a case which Atticus won.

Much of the pre-publicity has been the apparent dismantling of the Finch character, who as an older man is revealed as being a racist who believed in segregation: “Let’s look at it this way,” said her father. “You realize that our Negro population is backward, don’t you? You will concede that? You realize the full implications of the word ‘backward’, don’t you?”

Later in the confrontation, which occurs near the close of the book, Atticus puts it to Jean Louise, who has spoken in a most disrespectful way to him throughout the argument: “Then let’s put this on a practical basis right now. Do you want Negroes by the carload in our schools and churches and theatres? Do you want them in our world?”

Shocking as the sentiments expressed are, there is also the fact that the writing is very theatrical. “You are a coward as well as a snob and a tyrant, Atticus,” shouts Jean Louise. “When you talked of justice you forgot to say that justice is something that has nothing to do with people –”

Most of, no, all of the interest generated by this belated publication will focus on the deconstruction of Atticus Finch. It is similar to Captain Von Trapp being revealed as a Nazi sympathiser or Pongo, the father dog in Disney’s 101 Dalmatians, deciding to eat the puppies. But now that it is being published in an admittedly commercial rather than scholarship-driven context, it is only fair to read it in context – as a first version of a much-loved later book – not as a prequel.

The opening chapter has the feel of a short story; there is a tremor of anticipation. Jean Louise is coming home for two weeks; she is in a good mood, has survived her little tussle with the folding bed and muses upon the history of Maycomb County “so cut off from the rest of the nation that some of its citizens, unaware of the South’s political predilection over the past ninety years, still voted Republican. No trains went there – Maycomb Junction, a courtesy title, was located in Abbott County, twenty miles away. But service was erratic and seemed to go nowhere, but the Federal Government had forced a highway or two through the swamps, thus giving the citizens an opportunity for free egress. But few people took advantage of the roads, and why should they? If you did not want much, there was plenty.”

When the train does stop, Jean Louise’s father is not there to meet her. Instead she is greeted by a tall man who “grabbed her in a bear hug” and then kisses her. When she objects although “much pleased”, the third-person narrative proceeds in a knowing tone, which frequently surfaces: “the possessor of the right to kiss her on the courthouse steps was Henry Clinton, her lifelong friend, her brother’s comrade, and if he kept on kissing her like that, her husband. Love whom you will but marry your own kind was a dictum amounting to instinct within her. Henry Clinton was Jean Louise’s own kind, and now she did not consider the dictum particularly harsh.”

The flirtatious exchanges are played out against a backdrop of extensive information. In the midst of such detail is a blunt statement: “Jean Louise’s brother dropped dead in his tracks one day . . .”

Her brother is Jem, about whose arm injury Scout is reflecting in the polished opening paragraph of To Kill a Mockingbird: “When he was nearly thirteen my brother Jem got his arm badly broken at the elbow.” Jem’s sudden death is consistent with the heart attack which killed Scout’s mother when she was two.

The pieces keep coming together but for a reader it is more of an exercise in evolution. The belated publication of Go Set a Watchman is a publishing curiosity, but it is not a textual revelation destined to excite or even overly interest scholars.

Jean Louise has a harsh streak. In speaking with her aunt Alexandra, and Atticus, now stricken with rheumatoid arthritis, she retorts when asked about life in New York: “Right now I want to know about this big city. You two never write me any dirt. Aunty, I’m depending on you to give me a year’s news in fifteen minutes.”

Alexandra attempts to convince her to return home for good. “– you can get a job at the bank and go to the coast on weekends. There’s a cute crowd in Maycomb now; lots of new young people. You like to paint, don’t you?” Jean Louise seethes inwardly: “Like to paint. What the hell did Alexandra think she was going with her evenings in New York? . . . Jehovah. She catches me when I’m nearly out of my mind and lays out the avenues of my life. How can she be his sister and not have the slightest idea what goes on in his head, my head, anybody’s head . . .”

Aunt Alexandra had gone to live with Atticus because of his arthritis. This one kind gesture appears to establish a ceasefire. Yet the tension between the women culminates in the aunt remarking: “Jean Louise, your brother worried about your thoughtlessness until the day he died!” The rebuff causes Jean Louise to reflect: “It was raining softly on his grave now” (shades of the snow on Michael Furey’s grave in Dubliners) “in the hot evening. You never said it, you never even thought it; if you’d thought it you’d have said it. You were like that. Rest well, Jem.”

Elsewhere she thinks: “There’s nothing like a blood-curdling hymn to make you feel at home, thought Jean Louise. Any sense of isolation she may have had withered and died in the presence of some two hundred sinners earnestly requesting to be plunged beneath a red, redeeming flood.”

In the reading of Go Set A Watchman is the sensation of a writer engaging in the process, it is self conscious but it is interesting in the light of what would happen when Harper Lee went back to re-work it, which she did, three times, under the astute guidance of her editor Tay Hohoff, of Lippincott. A more fluid style emerged as did a convincing – and consistent narrative voice – that of the six-year-old Scout Finch.

No one could begrudge Harper Lee this final celebration. She has lived to see it being published. The publishers are hardly taking a chance; after all, To Kill a Mockingbird has sold about 40 million copies. The publication of her first work, which she described as “pretty decent effort”, may well draw more readers to To Kill a Mockingbird, which is a novel for readers of all ages. Go Set a Watchman is not. It is unlikely to be read aloud to children or studied at school. The prose is often quite coarse and Jean Louise’s outbursts against her father provokes her quiet uncle Jack into striking her across the face.

Yet its most satisfying sequences are the flashbacks at a church in which Scout and Jem are accompanied by Dill – inspired by Lee's childhood friend, the writer Truman Capote. By the time Capote and Lee set off to Kansas to research the Clutter family massacre which would become Capote's In Cold Blood, Lee had finished To Kill a Mockingbird; she knew how difficult it is to write a book. Capote, on the other hand, was a celebrated writer, author of Other Voices, Other Rooms (1948) and he did patronise her. She enjoyed huge fame but drifted as a writer under pressure to write another one. Her sister, Alice, kept Harper Lee's two manuscripts in her law office.

In a foreword for a new edition of To Kill a Mockingbird which was published in 1993, Harper Lee, true to her forthright personality, wrote: “Please spare Mockingbird an introduction. To novels, I associate introductions with long-gone authors and works that are being brought back into print after decades of internment. Although Mockingbird will be 33 this year, it has never been out of print and I am still alive, although very quiet. Introductions inhibit pleasure, they kill the joy of anticipation, they frustrate curiosity. The only good thing about introductions is that in some cases they delay the dose to come. Mockingbird still says what it has to say; it has managed to survive the years without preamble.”

She is quite right. Mockingbird still speaks and will continue to do so despite the deconstruction of its prevailing essence, Atticus Finch. To Kill a Mockingbird achieves a narrative ease born of close work; it strikes a balance between the heart and the mind. Go Set A Watchman is very different, far more disjointed, uncertain of its style and it will, unwittingly, introduce inconsistencies. At best it is exactly as Harper Lee said: “a pretty decent effort” – and not much more.

If there is a movie to be made, Gregory Peck is no longer alive to save it.