Inside Cover, Volume 114, Issue 22

The spin Hamiltonians (SHs), as a central tenet in magnetic resonance spectroscopies, provide a succinct description of various interactions such as electronic and nuclear Zeeman terms, electron exchange interaction, zero‐field splitting, spin‐spin, spin‐orbit, nuclear quadrupole, and hyperfine couplings. Using the quantum mechanical concepts such as effective Hamiltonians, perturbation theory, and unitary transformations, the tutorial by Mohammad Mostafanejad on page 1513 (DOI: 10.1002/qua.24717 ) addresses the basics of the SH formalism. Through the analysis of the electron magnetic resonance spectrum, the figure shows that how the spin density of an unpaired electron in Y 2 @C 79 N reflects invaluable information about its electronic and molecular environment.