Freeplane is a free and open source software application for bulding mind maps.

Freeplane aims for maximum ease and speed of use. Occupying the middle ground between an editor and a diagramming tool, Freeplane allows the user to add content as quickly and naturally as they would in a text editor, yet producing structured content that can be manipulated as easily as a diagram. The workflow is unimpeded by the need to think about and manually place each piece of information; the user can intuitively input content as paragraphs and headings, and easily reorganise at a later stage. The width and other aspect of each topic (node) can be set independently and a node can be defined to behave indepently from the nodes in the tree structure, to be free positionable.