The Astro Runtime (AR) is a platform-independent executable that, in it's typical configuration, runs in the background on the user's desktop. It hides the complexity of the emerging VO system behind a simple, stable, consistent, self-contained facade 

• It exposes an API of high-level VO functions. These functions can be invoked from other programs and are implemented using efficient, error-tolerant clients that call to VO web services through SOAP and HTTP
• This simplifies VO programming. Developers can start to address their problem immediately using the API. There's no need to learn, configure and code to SOAP toolkits or XML parsers! In short, less in-depth knowledge of VO standards is required
• As a shared component, it provides a single point of configuration and upgrade; manages credentials for single sign-on; caches often-requested data; and can be used for inter-application messaging with PLASTIC
• It's highly configurable and embeddable - available as a library, or as a stand-alone executable, and also as part of the AstroGrid Workbench.