Kaminari is a pagination library for Ruby on Rails and other web frameworks. It provides scope-based pagination for ActiveRecord models and generic arrays, with view helpers to render pagination controls. The architecture consists of three main components: kaminari-core (pagination logic), kaminari-activerecord (ActiveRecord adapter), and kaminari-actionview (view helpers). Key features include customizable pagination windows, optional count queries for performance, and support for multiple ORMs and template engines. The implementation demonstrates strong craftsmanship in its windowing algorithms, parameter handling, and the innovative 'without_count' optimization that avoids expensive COUNT queries by fetching one extra record.