Kadri's parallel travel writing career started with a visit to Prague during the 1989 Velvet Revolution, as one of only a handful of 'non-journalists' who actually observed the reality of the changes without being hamstrung by press conferences and filing deadlines. He stayed on in Prague for two years to pen the groundbreaking Cadogan Guide to that city. His 2005 book, "The Trial: A History, from Socrates to O. J. Simpson" was written after two and a half years spent in Manhattan, having arrived shortly before September 11, 2001. He was inspired to write his 2012 work "Heaven on Earth", by the September 11, 2001 and July 7, 2005 bombings. Critics have called that book "extremely valuable" and "entertaining", "carefully researched", and "thorough and admirable".