The first step in addressing a biological question is to build a biological network and establish dynamic relations among the nodes of the network. This can be done by starting with a sufficiently large network (using, for instance, Intelligent Pathway Analysis) and then proceed to reduce the (large) number of nodes. In this talk I will consider the reverse approach: starting with the very few nodes in terms of which the biological question is formulated, we keep adding “intermediate” nodes (cells, cytokines, genes) until the biology becomes sufficiently adequate to address the biological question. I will give two examples: fibrotic diseases, and cancer diseases.