Refers to the series of managed activities necessary to ensure continued access to digital materials for as long as necessary. Digital preservation refers to all of the actions required to maintain access to digital materials beyond the limits of media failure or technological and organisational change. Those materials may be records created during the day-to-day business of an organisation; "born-digital" materials created for a specific purpose (e.g. teaching resources); or the products of digitisation projects.
Digital Preservation Coalition: Digital Preservation Handbook
As technology continues to progress and evolve, the world of information is increasingly disappearing from physical manifestation and is largely comprised of digital materials. Digital materials, although durable through replication, are inherently fragile. They only exist and manifest in specific environments dependent on complex interlocking technical infrastructures. A PDF file may contain a ground breaking mathematical equation, a visual representation of years of valuable statistical research, or a beautiful poem. And yet, if this information is not rendered human readable by digital infrastructure, it is nothing more than a series of encoded bits.