~FatTable~ is a gem that treats tables as a data type. It provides methods for constructing tables from a variety of sources, building them row-by-row, extracting rows, columns, and cells, and performing aggregate operations on columns. It also provides as set of SQL-esque methods for manipulating table objects: ~select~ for filtering by columns or for creating new columns, ~where~ for filtering by rows, ~order_by~ for sorting rows, ~distinct~ for eliminating duplicate rows, ~group_by~ for aggregating multiple rows into single rows and applying column aggregate methods to ungrouped columns, a collection of ~join~ methods for combining tables, and more. Furthermore, ~FatTable~ provides methods for formatting tables and producing output that targets various output media: text, ANSI terminals, ruby data structures, LaTeX tables, Emacs org-mode tables, and more. The formatting methods can specify cell formatting in a way that is uniform across all the output methods and can also decorate the output with any number of footers, including group footers. ~FatTable~ applies formatting directives to the extent they makes sense for the output medium and treats other formatting directives as no-ops. ~FatTable~ can be used to perform operations on data that are naturally best conceived of as tables, which in my experience is quite often. It can also serve as a foundation for providing reporting functions where flexibility about the output medium can be quite useful. Finally ~FatTable~ can be used within Emacs ~org-mode~ files in code blocks targeting the Ruby language. Org mode tables are presented to a ruby code block as an array of arrays, so ~FatTable~ can read them in with its ~.from_aoa~ constructor. A ~FatTable~ table can output as an array of arrays with its ~.to_aoa~ output function and will be rendered in an org-mode buffer as an org-table, ready for processing by other code blocks.