Complex sentence: He also interviewed the dissident Soviet writer Boris Pasternak, then under surveillance, in 1959, smuggling out two poems by Pasternak, one of which was immediately published in the "Daily Mail".
Split into simpler sentences: He also interviewed the dissident Soviet writer Boris Pasternak, who at the time was under surveillance, in 1959. He subsequently smuggled two of Pasternak's poems back to the UK, one of which was immediately published in the "Daily Mail".