In higher eukaryotic cells the nuclear envelope is reversibly disassembled during mitosis. Under in vivo conditions this process occurs in a sequential, stepwise fashion and involves a variety of structural intermediates. Here we discuss the topological features of these intermediates and their transient interactions with chromatin and the cytoskeleton. As it becomes apparent, nuclear envelope disassembly and reassembly are regulated at multiple levels by modulating the affinity of protein-protein interactions, limiting the availability of structural subunits in different areas of the mitotic cytoplasm, and redirecting mechanical forces exerted by the microtubules.