The Cell Nucleus, Volume I reports the basic concepts of cell nucleus, including nuclear structure, the interaction between the nucleus and cytoplasm, and the chromatin. This volume first describes the nucleus’ morphological structures and relates these structures to its functions. It then discusses nuclear organization in plant cells; morphology and biochemistry of the slime mold nucleus; and structure, function, and properties of nuclear envelope. In addition, it addresses the molecular movements between nucleus and cytoplasm against a concentration gradient, presents experiments with animal cell heterokaryons, and explains the genome in specialized cells. It also explores the organization of the chromatin fiber; the human chromosome structure before and after banding; and the ultrastructure and function of heterochromatin and euchromatin.