Science-fiction writer William Gibson was one of the very few people to anticipate the information and communication revolution of recent years, and his novels have become renowned for their prophetic themes, as well as for their powerful and literary style. He talks to Laura Cumming about imagining the future as his latest work All Tomorrow's Parties takes us into a post-net world. And on national Poetry Day, Christopher Ricks discusses his new edition of the seminal anthology The Oxford Book of English Verse, and writer Iain Sinclair makes his case for one of The Lost Voices of British Poetry.