Information is at the core of the work of parliaments. Services that provide accurate, timely and impartial information are an essential resource for parliamentarians in carrying out their work and informing the decisions they take. This is the role of parliamentary libraries and research services. It has been over 25 years since the first edition of these Guidelines was published and, in that time, much has changed. The amount of information that is readily available to parliamentarians and citizens is now so vast it can be overwhelming.