This paper introduces a novel 2-dimensional (2-d) space-filling approach called *tree-maps* for visualizing complex tree structures, particularly useful for representing large directories and files on a hard disk. Traditional tree representations, such as rooted, directed graphs, are limited in their ability to display large structures effectively. Tree-maps address this issue by representing each node as a rectangle whose area is proportional to an attribute like file size. The algorithm recursively partitions a rectangular area based on the size of each node, ensuring that deeper levels cover previously drawn sections. This method provides a quick overview of relative sizes and allows users to identify large files for deletion or other operations. The paper discusses the practical implementation, including color coding for different attributes and the need for user controls to customize the visualization. Examples of tree-maps are provided, demonstrating their effectiveness in various applications, such as organization charts, library holdings, and stock portfolios. The authors continue to refine the technique, exploring new layouts and methods to handle large file size ranges.This paper introduces a novel 2-dimensional (2-d) space-filling approach called *tree-maps* for visualizing complex tree structures, particularly useful for representing large directories and files on a hard disk. Traditional tree representations, such as rooted, directed graphs, are limited in their ability to display large structures effectively. Tree-maps address this issue by representing each node as a rectangle whose area is proportional to an attribute like file size. The algorithm recursively partitions a rectangular area based on the size of each node, ensuring that deeper levels cover previously drawn sections. This method provides a quick overview of relative sizes and allows users to identify large files for deletion or other operations. The paper discusses the practical implementation, including color coding for different attributes and the need for user controls to customize the visualization. Examples of tree-maps are provided, demonstrating their effectiveness in various applications, such as organization charts, library holdings, and stock portfolios. The authors continue to refine the technique, exploring new layouts and methods to handle large file size ranges.