Professor Cai Wen was invited to give a lecture on Extentics in Guangzhou on May 22nd, 2009. The title of the lecture is “Studying Smart Knowledge—Common Lecture about Extentics”. About 200 people attended the lecture, mainly teachers and students from Guangzhou Urban Technology Academy and members of Popular Science Volunteer Society Professor Cai introduced smart discipline, the basic theories of Extentics, and the methods of becoming smart depending on lively stories in understandable language. The lecture is warmly welcomed by the audience.