LibreOffice is a free and open-source office suite that is compatible with other major office suites, and is available on all operating systems. It is an independently-developed version of the OpenOffice.org suite.
The office suite includes:
Writer, a word processor with similar functionality and file support to Microsoft Office Word. It has extensive WYSIWYG word processing capabilities, but can also be used as a basic text editor.
Calc, a spreadsheet program, similar to Microsoft Office Excel. It has a number of unique features, including a system which automatically defines series of graphs, based on information available to the user.
Impress, a presentation program resembling Microsoft Office Powerpoint. Presentations can be exported as SWF files, allowing them to be viewed on any computer with Adobe Flash installed.
Draw, a vector graphics editor and diagramming tool similar to Microsoft Office Visio. It provides connectors between shapes, which are available in a range of line styles and facilitate building drawings such as flowcharts. It also includes features similar to desktop publishing software such as Scribus and Microsoft Office Publisher.
Math, an application designed for creating and editing mathematical formulae.
Base, a database management program, similar to Microsoft Office Access.