The eukaryotic nucleus is highly dynamic and complex, containing several subcompartments, several types of DNA and RNA, and a wide range of proteins. Interactions between these components within the nucleus form part of a complex regulatory system that is only partially understood. Rapid improvements in proteomics applications have led to a better overall determination of nucleus protein content, thereby enabling researchers to focus more thoroughly on protein-protein interactions, structures, activities, and even post-translational modifications. Whereas proteomics research is quite advanced in animals, yeast and Escherichia coli, plant proteomics is only at the initial phase, especially when a single organelle is targeted. For this reason, this review focuses on the plant nucleus and its unique properties. The most recent data on the nuclear subproteome will be presented, as well as a comparison between the nuclei of plants and mammals. Finally, this review also evaluates proteins, identified by proteomics, that may contribute to our understanding of how the plant nucleus works, and proposes novel proteomics technologies that could be utilized for investigating the cell maestro.