Systems Biology is an open access journal publishing original peer-reviewed research articles in experimental and theoretical aspects of the function of biological systems at the molecular, cellular or organismal level, in particular those addressing the engineering of biological systems, network modelling, quantitative analyses, integration of different levels of information and synthetic biology.  In addition to the highest-quality original articles covering the entire field, each issue includes timely reviews of key primary research papers and topics in Systems Biology. Systems biology is an approach in biomedical research to understanding the larger picture—be it at the level of the organism, tissue, or cell—by putting its pieces together. It's in stark contrast to decades of reductionist biology, which involves taking the pieces apart.