Sylpheed is a simple, lightweight but featureful, and easy-to-use e-mail client (mailer, MUA). Sylpheed runs on Unix-like systems such as Linux, BSD, and Mac OS X. It also supports Windows. Sylpheed uses GTK+ GUI toolkit. The newest version of Sylpheed works with GTK+ 2.4 or later (2.6 or later is recommended). Sylpheed has the following features: * Simple, beautiful, and well-polished user interface * Comfortable operationality which is built in detail * Well-organized, easy-to-understand configuration * Lightweight operation * High reliability * Internationalization and Multilingualization support * High-level Japanese processing * Various protocols support * Security features (GnuPG, SSL/TLSv1) * Powerful filtering and search * Junk mail control * Flexible cooperation with external commands