E-Government emerged with the aim of providing greater integration between government, citizens and organisations through the dissemination of new Information and Communication Technologies (ICTs), particularly the Internet. As a result, the online portals of different public institutions emerged to meet the needs of communication between the Public Administration and society and to provide adequate and timely information to users of public services. In this book, the usability of the online e-Government service is evaluated in order to build an index that will allow it to be improved.