<p>"I have been working in the field of data since 1975. There is a file rouge that connects several of my contributions. Initially I started working on conceptual models, especially on the Entity Relationship  model and conceptual schema design, see the Benjamin & Cummings book, now Pearson, written with Ceri and Navathe. One of my contributions has been to define several desirable qualities of conceptual schemas. More recently, I have addressed the issue of Data quality, in the aspects related to dimensions and methodologies, see the Springer 2006 book with Scannapieco.  Later, I have worked on quality of information, addressing several representations such as semi-structured texts, unstructured text, maps and images.</p><p>In 2010, when preparing a tutorial for CAiSE in Hammamet, I arrived at the conclusion that a quite important cheer was needed on top of this cake, the issue of quality of models and languages used to produce conceptual schemas and databases, made of values (or data). Think e.g.  on the relational model, and to the elegant ways to express the concept of normal form in the model. Language or model, schema, values (or data) are all part of a same universe, and in a sense influence each other with reference to their desired qualities.</p><p>For these reasons, the book of John Krogstie, that deals with quality of languages and models, is quite relevant to complete this long and fascinating itinerary about  quality of information and data."</p><p>Professor Carlo Batini, University of Milano-Bicocca, Italy.</p><p>"The quality of a model should be aimed for in each step of the modeling process. This requires a thorough understanding of the quality characteristics of models and of their relevance in each step of the process.This book presents SEQUAL, a complete quality framework that is very useful for defining quality goals and analyzing their achievement in models, modeling processes and modelinglanguages."</p><p>Professor Antoni Olivé, Polytechnic University of Catalonia, Spain.</p>