Which C.S. Lewis book argues that modern education can weaken objective moral values?

The C.S. Lewis book arguing that modern education can weaken objective moral values is The Abolition of Man. It developed from three lectures Lewis delivered at the University of Durham in 1943 and was published as a book that year.

Lewis criticizes approaches to education that treat value judgments as merely subjective feelings. He argues for an objective moral order, which he calls the Tao, and warns that attempts to conquer nature through technological power may ultimately place humanity under the control of other humans.

The book is a philosophical work, not a novel, and it is much shorter than Lewis’s fiction. Its three chapters are titled “Men Without Chests,” “The Way,” and “The Abolition of Man,” followed by an appendix listing examples of traditional moral principles.