The world moves on. Since the ﬁrst edition of this book was written computer models of creativity have been developed which surpass those of the late 1980s. They include examples focussed on all types of creativity: combinational, exploratory and transformational. Like the programs discussed in the ﬁrst edition these are interesting for the light they throw on our own creativity. The two major bottlenecks remain the same: the need for domain expertise in deﬁning conceptual spaces, and the difﬁculty of identifying aesthetic values clearly enough for them to be expressed in computational terms.