This document provides information about various vitamins. It begins with an introduction to vitamins and their history. It then discusses the classification of vitamins as fat-soluble or water-soluble. Specific vitamins discussed in more detail include thiamine, riboflavin, and niacin. For each vitamin, information is provided about its chemical structure, functions, dietary sources, deficiency symptoms, and recommended intake levels. The document aims to educate readers about the essential roles of different vitamins in human health and biochemistry.