Two developed -dimensional as a tool covariance for the study mapping of mechanisms spectroscopy of radiation was originally -induced fragmentation of di- and tri-atomic molecules. The main problem arising in applications of covariance mapping to larger molecular species stems from the overwhelming spurious signals of no physical significance induced by fluctuations of experimental parameters. We have recently pioneered the self-correcting partial-covariance spectroscopy which eliminates the need for continuous monitoring of multiple fluctuating experimental parameters enabling covariance mapping of macromolecular decompositions. This opens the opportunity for mechanistic studies of macromolecular decompositions using covariance mapping. Moreover, we demonstrate that the two-dimensional partial covariance mass spectrometry (2D-PC-MS) based on the self-correcting partial covariance mapping has an unparalleled analytical capability. It enables confident reconstruction of the biomolecular sequences in the cases where the standard MS fails as a matter of principle – even at the theoretical infinite mass precision and resolution, as well as full sequence coverage by fragmentations. The sequence reconstruction can be automated both for peptides and for intact proteins.