​LibreOffice is a complete open source alternative to Microsoft Office.  It includes, Writer (word processing), Calc (spreadsheets), Impress (presentations), Base (databases), Math (formula editing), and Draw.  Draw is an alternative to Microsoft Publisher for creating multi-page layouts.  Open, edit, and create many different file formats including .PUB, .PDF, .DOC, .DOCX, and many more!

Open Office has become the free standard for Office software.  With a familiar layout and feel, Open Office provides a quality, free alternative to Microsoft Office. Open Office will also open, edit, and save in file formats compatible with MS Office!

More details from the OpenOffice.org website are listed below:

• Writer a word processor you can use for anything from writing a quick letter to producing an entire book.
• Calc a powerful spreadsheet with all the tools you need to calculate, analyze, and present your data in numerical reports or sizzling graphics.
• Impress the fastest, most powerful way to create effective multimedia presentations.
• Draw lets you produce everything from simple diagrams to dynamic 3D illustrations.
• Base lets you manipulate databases seamlessly. Create and modify tables, forms, queries, and reports, all from within Apache OpenOffice.
• Math lets you create mathematical equations with a graphic user interface or by directly typing your formulas into the equation editor.

If you need an office suite capable of producing, editing, and viewing Microsoft Office files, Kingsoft Office may be just what you are looking for.  Their free version has the equivalent of Word, Excel, and PowerPoint, and all with a similar feel and layout to their expensive counterpart.