Himalaya is a command-line interface (CLI) tool designed for efficient email management, built using Rust and based on the `email-lib` crate. It supports multi-account configurations through an interactive wizard or manual TOML-based setup. Key features include IMAP, Maildir, Notmuch, SMTP, and Sendmail backends, along with PGP encryption options and OAuth 2.0 authentication. It offers JSON output for scripting, integrates with system keyrings for secure credential storage, and allows message composition via `$EDITOR`. Himalaya is highly modular, with functionalities enabled or disabled via Cargo features. It is cross-platform, with installation options including pre-built binaries, Cargo, and package managers like Homebrew and Scoop. Ideal for developers and power users, it provides a stateless, scriptable approach to email handling.