Introduction modest is a mail user agent (MUA) targetting small devices, in particular Nokia's Nokia 770 Internet Tablet. This document describes the design and implementation of this software. modest lives at the top of a extensive stack of software. It is built on top of tinymail, and uses its libcamel backend. It strives to the be a simple yet powerful program, geared towards small devices, for example (but not limited to) Nokia's 770 internet tablet. An important goal is to minimize memory usage while still being able to handle significant amounts of email quickly; much of that is achieved simply by using tinymail, which uses a number of clever tricks for that, such as the proxy design pattern for listing email headers, and not needing memory for headers which are not currently visible. modest, in turn, also tries to be efficient, fast and scalable. That means that the MUA should support multiple user-interfaces, perhaps making it even possible to switch between them during runtime. To summarize the goals for modest: target devices with limited amounts of memory ('limited' in 2006 terms means less than 64Mb, and of which only part can be used for e-mail); target Linux/Unix-like environments with GLib/GTK+-based support; support multiple user-interface (UIs) with as much code sharing as possible between the different UIs. Like tinymail and libcamel, modest is programmed in C, using the GObject-system for object-oriented (OO) features. For now, it specifically targets \gtk based UIs (and derivatives like 'Hildon').