Microsoft Office is a set of interrelated desktop applications, servers and services, collectively referred to as an office suite, for the Microsoft Windows and Mac OS X operating systems. Office was introduced by Microsoft in 1989 on Mac OS, with a version for Windows in 1990. Initially a marketing term for a bundled set of applications, the first version of Office contained Microsoft Word, Microsoft Excel, and Microsoft PowerPoint. Additionally, a "Pro" version of Office included Microsoft Access and Schedule Plus. Over the years, Office applications have grown substantially closer with shared features such as a common spell checker, OLE data integration and Microsoft Visual Basic for Applications scripting language. Microsoft also positions Office as a development platform for line-of-business software under the Office Business Applications (OBA) brand.
The current versions are Office 2007 for Windows, launched on January 30, 2007, and Office 2008 for Mac OS X, released January 15, 2008. Office 2007/Office 2008 features a new user interface and a new OOXML-based primary file format (docx, xlsx, pptx). Microsoft has made available a free add-on known as the "Microsoft Office Compatibility Pack" that lets Office 2000-2003 editions open, edit, and save documents created under the new Office 2007 formats.