 He also illustrated several books by other various authors, before writing his own book - based on the idea of Townscape - in 1961.The Concise Townscape has subsequently been republished around 15 times, proving to be one of the most popular books on Urban Design in the 20th Century.In 1956 Cullen became a freelance writer and consultant and, in the years immediately following he advised the cities of Liverpool and Peterborough on their reconstruction and redevelopment plans.