The sections in this article are: 1 Light Microscopy of Adipose Tissues 1.1 Brown and White Adipose Tissue Organization 1.2 Histology of the White Adipose Cell 1.3 Histology of the Brown Adipose Cell 1.4 Histochemistry of Brown and White Adipose Tissues 1.5 Similarity of the Morphology of Developing White Fat and Brown Fat 2 Electron Microscopy of Adipose Tissues 2.1 Introduction 2.2 Materials and Methods 2.3 Differentiated White Adipose Cells 2.4 Differentiated Brown Adipose Cells 2.5 Experimentally Altered Brown Adipose Tissue 2.6 Differentiating White Adipose Cells 2.7 Persistent Differentiation of White Adipose Tissue 2.8 Transport of Particulate Lipid; Sites of Lipolysis or Lipogenesis 3 Summary