Dear Editor,

The article “Indentation Fracture Toughness: A Review and Application” by Relias and Ngai in the September 2018 issue is a shallow review and very misleading. For example, the last sentence in the first paragraph states: “… makes it a preferred choice for estimating fracture toughness of brittle materials.¹” Reference 1, which was written by Professor Bradt and myself¹, made it clear that the Vickers indentation fracture (VIF) method is not preferred and is a terrible choice. It cannot be relied on for accurate and precise fracture toughness data. Many experts agree, and there are many warnings in the literature.^{2, 3, 4, 5, 6, 7, 8, 9, 10}