1) Explanation

Let's break down the sentence to understand the meaning required for the blank:
- "Michalewski's text indubitably serves as the $\qquad$ of his discipline;"
- "Indubitably" means without a doubt. So, the text unquestionably holds a certain status within its field.
- "it surpassed all previous models of excellence and has replaced them with the rigor of heretofore unmatched academic standards."
- This is the crucial part. The text didn't just meet standards; it surpassed all previous models of excellence and replaced them with unmatched standards. This indicates that the text represents the absolute peak, the highest achievement, or the ultimate example in its discipline.

Now, let's evaluate the given options:
- A. validation: The action of proving or confirming something. While the text might validate the discipline, this word doesn't convey the sense of surpassing all previous excellence and replacing standards with unmatched rigor.
- B. vainglory: Excessive pride in oneself or one's achievements; excessive vanity. This is a negative term describing a personal trait, not the status or quality of a scholarly work.
- C. apotheosis: The highest point in the development of something; a culmination or climax. This word perfectly fits the context, meaning the text is the ultimate example, the peak of excellence, and the culmination of the discipline's standards, having surpassed all prior achievements.

- D. munificence: The quality or action of being lavishly generous. This term relates to generosity, which is irrelevant to the context of academic standards or excellence.
- E. beneficence: The quality of being kind or charitable. Similar to "munificence," this relates to good deeds or charity, not academic rigor or superiority.

Conclusion:

The word "apotheosis" most accurately captures the idea that Michalewski's text represents the ultimate achievement and sets unparalleled standards within its field.