The two most famous and enduring works of Daoism (or Taoism), both composed during the classical period of Chinese thought (c.500–200 BCE), are the Daodejing and the Book of Zhuangzi. The Zhuangzi is a classic of what is often labelled 'philosophical Daoism'. The qualifier is important, since the form of Daoism the Book represents needs distinguishing, despite certain affinities, from the organized religion of Daoism that developed after the second century CE. The Dao is the Way of nature as a whole, so that 'the true man', who is 'lost in Dao', is one who, like a fish, lives 'naturally'. Moreover, as the Way of nature as a whole, the Way is 'spontaneous' (ziran) and 'free'. To live 'naturally', 'lost in Dao', is to act spontaneously, flexibly and intuitively, without rigid attachment to conventional rules and distinctions, linguistic, moral or other.