The Shadow Girls, By Henning Mankell. Harvill Secker, £17.99

In interviews, Henning Mankell is always eminently cordial and polite – but journalists have learned that he expects his interlocutors to be well prepared. He is, however, patient with those who do not realise that his crime fiction is only one element of his output. "There are countries," he has said, smiling, "where I am better known for my non-crime novels than my Wallander books."

The title of The Shadow Girls may suggest thriller material, but the novel is a strange mélange of elements. The abandoning of a ship (with its black passengers left to their fate) is straight out of Conrad's Lord Jim, and the picture of the hopeless life of refugees suggests that we are in for a sinewy drama channelling the author's own charity work in Africa. Here, surely, is Mankell the socially committed writer, addressing issues that really count for him. We meet a young black woman refugee, "Tea-bag", convinced that Sweden is where she can start a new life. But like so many Africans smuggled into Europe, she is to find herself undervalued and despised.

However, Mankell then shifts gear with the appearance of barely successful poet: Jesper Humlin. Suddenly, we are in the kind of literary comic novel colonised by such writers as Malcolm Bradbury, with Jesper henpecked by his lover and his own mother. His agent bullies him into writing a crime novel instead of his poorly selling poetry.

Mankell's comic writing is not his strongest suit, but the set-pieces here are enjoyable, such as a disastrous poetry reading at which Jesper is heckled by immigrants. It is here that Mankell pulls off a coup. Sitting in the audience is the woman we encountered at the beginning of the book. She got into Sweden and wants Jesper to tell her story.

The book's real agenda becomes clear: Mankell is giving a voice to those who do not possess one. Some may feel that there are two kinds of novel here, which remain obstinately heterogeneous. But such is Mankell's skill that we surrender to whatever mode the book settles into. It might be argued that his comic sugaring of the pill in The Shadow Girls makes the hidden agenda all the more potent.