This book gives a complete description of online hemodiafiltration, in five sections. It is unique in the systematic and complete way in which hemodiafiltration is described. Each chapter is completed by a point-to-point summary of essential information, in a separate text box. Part of the book is dedicated to the theoretical background of convective clearance. In this part, safety issues and quality control is reviewed (especially on the quality of water for dialysis and substitution fluid), as well as equipment (both dialyzers and machines) with which this treatment can be performed. As recently the results of several randomized controlled trials were available, the effect of hemodiafiltration on hard clinical end points (mortality and morbidity) is discussed in detail. This has not been done before, as the most recent book/journal on hemodiafiltration was published in 2011, before the results of the 3 randomized controlled trials were published. Furthermore, the methodological quality of the trials is discussed by an expert, in order to help the readers in their judgment of the trials Part of the book concentrates on the effect of the treatment on several biomarkers and uremic toxins. Several clinically relevant issues is discussed separately, such as the prescription of anticoagulation during the treatment, drug prescription and clearance for patients treated with hemodiafiltration, and hemodynamic stability. Finally, a practical guide on how to perform the treatment is provided. In this unique section, seemingly simple but important details of hemodiafiltration-treatment is discussed, such as the importance of needle size for blood flow rates, the difference between filtration fraction and substitution ratio, the different targets that can be set and how to reach them. As most literature is mainly focused on theoretical issues, this unique feature really will help the field to perform hemodiafiltration, and answer practical questions.