It's the largest contemporary art festival in the UK, but Liverpool Biennial returns this weekend with a firmly international focus. The intriguing working title – <em>The Unexpected Guest</em> – might initially sound like the city is not quite sure who will turn up, but there's a more thoughtful concept at play here. The biennial has asked more than 60 artists from across the world to explore the idea of hospitality. The programme notes talk of not just the welcome extended to strangers, but how globalisation and migration between nations and cultures inspires artists. In that context, the participation of the London-based Israeli artist Oreet Ashery makes perfect sense. Ashery left Jerusalem in 1987 for both personal and political reasons. As a teenager, she joined peace movements and went on marches opposing the occupation of Palestine, but was called up for army service. After desperately trying to avoid what she has previously called "the nationalistic militant mentality" in Israel, she moved to the UK and her art career blossomed, producing site-specific work in a variety of guises, including an orthodox Jewish man, a fat farmer and a rabbit. Almost 25 years later, she's still having fun investigating race, gender and the Arab and Muslim world, and her work at Liverpool, <em>Party For Freedom</em>, is a film that deftly investigates why immigration and Islam is still seen by some as a threat to western values of freedom. "<em>Party For Freedom</em> refers to the Netherlands' right-wing political party, whose leader really did claim that Islam was a threat," she explains while on a break from installing her work. "It's a ridiculous statement, obviously, so what I've tried to do through the visuals and the music is make his statements seem almost comical. I think, when you pick apart propaganda like this, the paranoia becomes obvious." Ashery isn't the only artist at Liverpool Biennial to explore the Arab diaspora. Mona Hatoum, who was born in Palestine and settled in the UK when the Lebanese civil war broke out, doesn't like to think of her work as purely "about Palestine", but admits it has a political dimension. She brings a selection of recent works that largely use the idea of the map to explore cultural or political ignorance. <em>In Afghan (Red And Black)</em>, a traditional carpet appears to be worn out and ready for the tip. It's only when you look again that you realise the worn areas are actually a world map. <em>Present Tense</em>, a map of territories intended to be returned to Palestinian control after the 1993 Oslo Peace Accord, is made of olive-oil soap from Nablis, in the hope that one day the borders, like the soap, will be washed away. Liverpool Biennial also offers another opportunity to see Kader Attia's <em>Oil And Sugar #2</em>. The French artist, who is of Algerian descent, pours motor oil on to a cube of sugar. As the white solid crumbles and dissolves into the viscous oil, it's difficult not to note the contemporary metaphors of politics and religion. His other work at the festival, <em>Untitled</em> (Ghardaïa), is similarly dramatic. It seems like a scale model of the Algerian World Heritage Site so beloved of the legendary Western architect, Le Corbusier, but closer inspection reveals Attia has constructed the entire piece from couscous. Ashery, Hatoum and Attia are only a small part of this huge festival of art, which opens with <em>The Source</em>, the film exploring the creative process by the Californian artist Doug Aitkin. Tilda Swinton and Jack White are among the commentators, and the film is to be screened inside a special pavilion created by the architect David Adjaye. Nevertheless, there is the feeling that art inspired by the Arab world is making its mark. "I must say, in some ways, it doesn't seem like the understanding of cultures alien to the West is getting any better, especially when you still see such huge incidences of hatred," says Ashery. But then, showing work at Liverpool Biennial does prove there is much more awareness and consciousness, that people aren't sucked into the propaganda. It's a long, long journey we're on." <strong>• Liverpool Biennial runs from Saturday until November 25. Visit <a href="http://www.biennial.com">www.biennial.com</a></strong>