Which C.S. Lewis book argues that eliminating objective values would damage humanity?

The C.S. Lewis book arguing that eliminating objective values would damage humanity is The Abolition of Man.

Published in 1943, the book developed from lectures Lewis gave at the University of Durham. He criticized an approach to education that, in his view, treated value judgments as merely subjective emotional reactions. Lewis argued that moral education requires recognition of objective values, which he called the Tao in the work’s broader philosophical discussion.

The book is a short philosophical and educational critique rather than a novel or autobiography. It is often discussed alongside Lewis’s Christian apologetic writings, but its argument draws on moral philosophy, education, and cultural criticism. The title does not refer to the physical extinction of humanity; it refers to the transformation or loss of qualities Lewis considered distinctly human.