The Cells, Molecules and Bones Training Module is an interactive set of chapters designed to educate the learner on the building blocks of bone tissue: cells. Each type of bone cell is explored, as are the parts of these cells relevant to the process of bone healing and remodeling. The processes of cell proliferation through the cell cycle, cell differentiation and protein production are explored, as are the processes that regulate these activities. An explanation of the role of external and internal signals will be offered, including discussion of a particular intracellular signaling protein called mTOR. Finally, the interaction between the different bone cells will be discussed in the context of bone healing and remodeling. In addition, select local and systemic growth factors and hormones important to the regulation of bone formation will be reviewed. Throughout the module, bonus information will be available for those learners who wish to delve further into the material. This information is not mandatory for quizzes or exams, but a special "bonus quiz" will be given for those who wish to complete it.