Guidance Software are the producers of Encase - a venerable forensics tool for the Microsoft Windows Platform.
Quoted from the Encase website
Guidance Software was founded with a clear purpose: to develop solutions that search, identify, recover and deliver digital information in a forensically sound and cost-effective manner. Since our founding in 1997 we have moved into network-enabled investigations, enterprise-wide integration with other security technologies, and now, have powerful search and collection capabilities for eDiscovery and other investigations. Yet we haven't strayed from our core competency and continue to be widely recognized for quality and value.
Guidance Software's suite of EnCase® solutions provide an enterprise investigative infrastructure that enables corporations, government and law enforcement agencies to conduct effective digital investigations, respond promptly to eDiscovery requests and other large-scale data collection needs, and take decisive action in response to external attacks.