When models and data disagree, the strong modeler seeks to revise the model, whereas the strong experimentalist seeks to improve the dataset. The inverse modeler, on the other hand, recognizes that there is wisdom in both points of view and seeks the truth in the gap between models and observations. In this tutorial, I will demonstrate the difference between forward and inverse models with a toy biogeochemical model. Furthermore, I will briefly introduce global ocean modeling with the Ocean Circulation Inverse Model (OCIM), a state-of-art transport matrix model that has been used with great success. This tutorial is designed for students and early-career scientists interested in learning more about inverse modeling. Modeling novices welcome!