John Banville’s novel revolves around Freddie Montgomery, a former scientist who becomes a murderer after he kills a maid, Josie Bell, while attempting to steal a Dutch painting from a family friend. Unreliable and narcissistic, Freddie narrates his trial and his life before and after the murder.
Besides Freddie, there are few other important characters. There is Josie Bell, the servant girl he murders; Daphne, his wife, whom we only hear about through his skewed perspective; Charlie French, an old family friend that houses Freddie without knowledge of the murder; Freddie's mother and father; and Inspector Haslet. Other characters remain relatively peripheral.
Most details about Freddie’s character can be summed up in a few words; his relationships with others are, at best, tepid, and at worse, like with his mother, full of bitterness and disappointment. For the reason that Freddie remains the most important character, and that, plot-wise, very little occurs in the novel, I would like to suggest reading him as a postmodern figure. This would hopefully guide you toward a better understanding of postmodernism itself, which lies at the heart of the novel.
In Jean-François Lyotard’s seminal text The Postmodern Condition, he describes the postmodern as “an incredulity towards metanarratives.” In simple terms, metanarratives are the systems or structures that are deemed “normal,” right, true, and the only way of living. Explicit examples include racism, heterosexism, and sexism. These structures of oppression attempt to impose order onto reality and are made to appear as inviolable and monolithic.
In The Book of Evidence, multiple metanarratives are criticized. Throughout, Freddie questions language and its ability to convey “truth,” if there is any, given that language itself betrays bias:
By the way, leafing through my dictionary I am struck by the poverty of language when it comes to naming or describing badness. Evil, wickedness, mischief, these words imply an agency, the conscious or at least active doing of wrong. ... I ask myself if perhaps the thing itself—badness—does not exist at all, if these strangely vague and imprecise words are only a kind of ruse, a kind of elaborate cover for the fact that nothing is there. Or perhaps the words are an attempt to make it be there? Or, again, perhaps there is something, but the words invented it.
Freddie not only interrogates the inadequacy of language and its "poverty" but also suggests that the "badness" implicated in moral words—their belief in an innate good and bad—is conjured by the words themselves. Paradoxically, their ethical connotations are only there because the words make them out to be. Language and words draw attention to themselves, bringing to light their artificiality, in classic postmodern self-referentiality.
Self-referentiality, along with intertextuality, are other postmodern tenets that play big roles in the novel. Because postmodernism is central to the text, reading up on some of its key features might help guide you in understanding its characters.