Here's why:
* Glossary: Explains terms and concepts used within the text. It's meant to be consulted during reading to understand specific words or phrases.
* Index: Lists topics and names mentioned in the text, along with their page numbers. It's used for finding specific information within the book.
Therefore, a reader would typically use the glossary to understand the text and then use the index to locate specific information later. This logical flow makes it sensible to place the glossary before the index.