You have the three major prophets, Isaiah, Jeremiah and Ezekiel, and then the twelve minor prophets, which in the Hebrew Bible get counted together as one book, because those twelve are very small.

先知书里有三大预言家，以塞亚，耶利米和以西结，后来还有12个小先知，他们因为很小所以，全部被收入了一卷。

耶鲁公开课 - 旧约导论课程节选