It is now over ten years since we edited the first edition of HLA-B27 in the Development of Spondyloarthropathies (SpA). It is obvious that over this period an enormous amount of information concerning SpA and HLA-B27 has accumulated, and this has been reflected in the knowledge of molecular mechanism of the spondyloarthropathies. Discussion for such a book took initial form at the outstanding 4th Gent Symposium on SpA in October 2006, but was not formally commissioned by Landes Bioscience until early 2007. "Molecular Mechanisms of Spondyloarthropathies" aims to synthesize this growing knowledge and presents all the current studies concerning the basic research of SpA. Over the last decade, enormous progress has been made in the understanding of the molecular and cellular processes that lead to disease pathology. Recognition of the pathways involved in the pathogenic mechanisms of disease and the potential to target specific immune effector functions have opened the door to a wide range of innovative treatment opportunities for the SpA. Thus, we believe that the understanding of the specific molecular mechanisms involved would help to design highly specific drugs in the future. The contributors are among the best in their field and reflect the state of the art of research and current opinion of rheumatologists and immunologists.