Technically, a digital library is built up from simple components, notably digital objects.
A digital object is a way of structuring information in a digital form, some of which may be metadata, and includes unique identifier called a handle.
A single work may have many parts, a complex internal structure and one or more arbitrary relationships to other works. To represent the complexity of information in the digital library, several digital objects may be grouped together, this is called a set of digital objects.
All digital objects have the same basic form, but the structure of a set of digital objects depends upon the information upon the information it represents.
Some common digital objects are: