The Han imperial bibliography records a Zhuangzi in fifty-two sections, the shape given it by the librarian Liu Xiang. That version is lost. What survives is the edition of Guo Xiang, who died in 312 CE, and who cut the text to thirty-three chapters, discarding material he judged fantastic or philosophically worthless, and attached a commentary that became as influential as the text. Within a few centuries his recension was the only one in circulation, so everything modern readers have passed through the judgement of one fourth-century editor.
The thirty-three fall into three groups: Inner Chapters one to seven, Outer Chapters eight to twenty-two, and Miscellaneous Chapters twenty-three to thirty-three. The division is old and it tracks something real. The Inner Chapters share a vocabulary, a style and a set of preoccupations, and scholarly consensus assigns them to Zhuang Zhou, a minor official from Meng conventionally placed around 369 to 286 BCE, though the dates are inferences rather than records.
The Outer and Miscellaneous chapters are demonstrably not by one hand. Analysis of their language and argument, most influentially by A. C. Graham, separates out several strands: writers who idealise a primitive society before rulers and ritual, writers close to the individualist Yang Zhu, and later syncretists who fold in cosmology and statecraft and are trying to fit the book into a Han imperial worldview. Some chapters attack Confucius; others put respectful words in his mouth.
The practical result is that quoting the Zhuangzi requires knowing which chapter. A position in chapter twenty-nine may contradict chapter two flatly, and often does.