Get the movie before the book, writes Donald Clarke

Before Grand Theft Auto IV arrived at Screenwriter Plaza and I took to wearing a nappy, eating upholstery and sleeping beneath the coffee table, I had been spending my free time reading the source novels for some of this year's more prestigious movies.

Both José Saramago's Blindness, the basis for the drama that opened Cannes, and Richard Yates's Revolutionary Road, Sam Mendes's upcoming adaptation of which finally reunites Kate Winslet and Leonardo DiCaprio, proved to be fine pieces of work. But have I done the right thing by reading them?

Let me reformulate the question in a way that provides a more secure basis for pondering: Is reading the source novel for a movie likely to improve the film- going experience?

A certain class of half-bright phoney - the sort of person who regards cinema as an inherently inferior art form to literature - would think the question hardly worth asking. Since the "film is never as good as the book," you should always crack open the paperback and ignore any concerns about spoiling your night at the cinema. Folk who feel this way have, obviously, never read The Godfather, Jaws, Psycho or The French Connection (or seen the vastly superior films adapted from those books).

The average fan of Harry Potter might also wrinkle his brow at such a supposed dilemma. The films adapted from JK Rowling's books are so tediously faithful to the sacred text that they barely forge an independent existence.

Enthusiasts for Potter - and, to an extent, for The Lord of the Rings - expect to be able to mentally follow the novel as they watch the film, in the same way that classical music buffs used to monitor the score while musicians sawed away at their favourite cantata. "Mike Newell's left out an elf!" the mob screams. "Let's light torches and march on Castle Warner Brothers."

Rational punters who enjoy books as much as they enjoy movies may, however, have reasonable justification for pausing before plunging into the literary inspiration for an upcoming release. It hardly needs to be said that advance awareness of certain plot twists in a thriller may impair the viewer's enjoyment.

But, even when encountering an adaptation of a piece of literary fiction, the cinemagoer can find his knowledge of the source material a drag upon his enjoyment. You finds yourself filling in narrative gaps that the screenwriter may have deliberately inserted to spur creative ambiguity. Alterations in the characters' personalities will struggle to dent the fully formed fictional character already embedded in the reader's brain. You will, most likely, fail to suppress an instinct to compose a mental balance sheet setting what has been retained against what has been jettisoned.

So have I done the wrong by reading Revolutionary Road and Blindness? Probably not. By the time either film reaches Ireland, over-exposure to Grand Theft Auto should have reduced my brain to grey semolina. All going well, I'll barely be able to remember my own name, never mind the plot of some highbrow novel.

dclarke@irish-times.ie