This standard includes data elements that are exchanged or are potentially exchanged among bibliographic systems. Those elements that are not exchanged or not likely to be exchanged are ignored as they do not need standardisation. Data elements being handled by transport protocols are not included, only those related to application level protocols. The standard was previously published in five parts as follows: Part 1: Interloan applications (1988) Part 2: Acquisitions applications (1992) Part 3 : Information retrieval applications (1994) Part 4 : Circulation Applications (1998) Part 5 : Data elements for the exchange of cataloguing data and metadata (2002) The elements from these 5 parts have been examined, updated where necessary and consolidated into a single set of elements such that this standard replaces these previous parts. The data elements have been broadly classed and sub-classed and are presented in two sequences, one by class and sub class and an alphabetical index. The alphabetical index includes synonyms identified during the consolidation phase and those found in related interchange protocols and schemas. As the grouping of elements may differ among different protocols and record schemas, the elements have been broadly classed and grouped but no further structure has been made. Similarly the sequence of elements, whether or not an element is mandatory or how it is structured and validated may vary according to its employment and consequently these element attributes are out of scope for this standard. As new ways of inter-operating evolve, some new data elements may evolve but the biggest change is usually in the way that existing elements are grouped. For example, whether a purchase transaction is carried out manually or electronically, the base elements of the transaction, requester, supplier and object of purchase remain constant and this is reflected in the fact that most data elements in this standard originated several decades ago. To accommodate the potential changing grouping of elements, an attempt has been made to identify common concepts across processes. For example a new focus on end user delivery is causing diverse delivery options to be grouped together such that purchase, loan and inter-library loan processes are presented as alternatives, therefore the identification of common concepts in all these processes is necessary for the development of seamless user interfaces.