Here's why:
* Sets the stage: The introduction is where you capture the reader's attention and introduce the topic. The thesis statement acts as a roadmap, clearly stating the main argument or point of the essay.
* Provides focus: It gives the reader a clear understanding of what the essay will be about and what the writer's stance is.
* Guides the reader: The thesis statement helps the reader follow the flow of your argument as they read through the supporting paragraphs.
While it's usually at the end of the introductory paragraph, the exact placement might vary slightly depending on the length and complexity of the essay.