Explore data preparation techniques for effective visualization using Altair in this comprehensive video tutorial. Learn why data transformations are crucial and how to apply them to movie datasets. Master aggregate transforms, axis sorting, and statistical measures like mean and median. Discover how to visualize interquartile ranges, create histograms, and implement time unit transforms. Dive into calculate and filter transforms, essential for data manipulation. Follow along with provided code notebooks and additional resources to enhance your understanding of Altair's powerful features for data visualization.