Pathobiochemistry means biochemistry of disease. In the curriculum of medical studies it may serve as a useful and highly enjoyable “bridge” between the basic science of the first years, and the clinical training later. Practical limitations dictate that from a vast area of human pathology a careful selection of topics must be made. The eleven chapters of this book deal with the basics of acid-base balance disorders, inflammation, reactive oxygen species and antioxidant defense, non-enzymatic glycations, atherosclerosis, metabolic syndrome, ischemia/reperfusion of the heart, protein misfolding disorders, ageing, and consequences of alcohol abuse. The selection covers some pathogenetic processes behind several important medical problems of the present. Further, it more or less implicitly points to the inner causes of diseases. The inner maintenance of body structural and chemical integrity is costly and has its limits that regularly get exceeded, which is the ultimate reason for ageing and contributes to many, often also age-related, civilization diseases.