The Journal of Combinatorial Theory publishes original mathematical research dealing with theoretical aspects of the study of discrete structures. Series B is concerned primarily with the theory of graphs and hypergraphs as well as matroids, and is a valuable resource for mathematicians and computer scientists.As one of the premier journals in these areas, the journal sets very high standards for publication. Manuscripts accepted by the journal are generally expected to solve or make an important step towards a solution of an open problem, to develop a new proof technique, or to substantially advance our knowledge in some other way.The journal imposes even higher standards for accepting very long papers.The editorial process consists of two phases. In the first phase, the journal seeks general opinions from our editorial board and other experts. Only those papers that obtain favourable recommendations in this phase proceed to the second phase which involves a detailed refereeing process.