The European Commission, DG XII, has published a review, carried out by the Complutense University of Madrid, of problems and potential solutions in the field of paper recyclability entitled "Paper recycling: An introduction to problems and their solutions". The need for this review was established during work in the course of COST Action E1 on Paper Recyclability, undertaken within the COST initiative for European cooperation in the field of scientific and technical research. Competitiveness is no longer the sole issue for the paper industry, with the key issue now that of finding the right balance between competitiveness and sustainability issues. The final product is no longer considered solely in terms of process efficiency and product quality, but also in terms of sustainable production and minimal impact on the environment. This review will therefore be useful to all those who have an interest in paper recyclability, and should help to improve fundamental understanding of the problems associated with the accumulation of contaminants during paper-making. Furthermore, the work should identify gaps in existing research and point the way for future research. The book is divided into six chapters which deal with the following: - A general overview of the paper recycling industry; - Water management in the paper industry; - A survey of the state-of-the-art of stickies deposits during paper-making; - Nature, sources and formation of white pitch deposition; - Inorganic dissolved solids: Salt sources and the influence of high salt content in the process of paper-making; - Microbial aspects in the recycling paper industry.