This is the software publisher’s description.

Sophos Anti-Rootkit is a tool that servers one purpose, in that it eliminates hidden applications and processes that were installed on your system by malicious software.

The term rootkit is used to define a Trojan (or technology) used to hide the presence of a malicious object (process, file, registry key, network port) from the computer user or administrator.

As part of its complete protection of endpoint computers, Sophos Anti-Virus detects rootkits and prevents them being installed on any of your desktops, laptops and servers. Sophos Anti-Rootkit provides an extra layer of detection, by safely and reliably detecting and removing any rootkit that might already have secreted itself onto your system.

Download the manual which is in PDF format.

The new 1.3.1 contains enhanced detection capabilities and many minor fixes and enhancements.