This chapter summarizes the methodology of bone histomorphometry and highlights the tissue-level characteristics of normal and abnormal bone development. Bone histomorphometry is a key tool for studying bone tissue. Both the activity of bone metabolism and the amount and distribution of bone tissue are analyzed with unsurpassed resolution. Between birth and adulthood, bones undergo considerable increases in size. The most frequently assessed aspect of this process is longitudinal bone growth, as reflected by body height. The increase in bone length is mostly due a mechanism called endochondral ossification. The primary effector cells of this process are growth plate chondrocytes. These cells continuously divide and synthesize a cartilaginous matrix, which, in a stepwise process, is subsequently converted into osseous tissue. Bone histomorphometry mostly provides information on two other aspects of bone development, bone remodeling, and bone modeling. A process named remodeling renews bone created by endochondral ossification. Remodeling consists of successive cycles of bone resorption and formation on the same bone surface. The basic features of this process are identical for trabecular and cortical bone.