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Specific heat is a direct probe of low-energy excitations, positioned to capture both the electronic density of states and the scaling of quantum-critical fluctuations in strongly correlated materials as functions of temperature, magnetic field, and orientation. In this seminar, I will introduce our nanocalorimetry platform for high-resolution measurements at low temperature and in strong magnetic fields. I will also describe our recent extension of the technique from steady-state measurements to frequency-domain calorimetry (“thermal impedance spectroscopy”). This dynamic approach enables concurrent extraction of spin–lattice relaxation time T1 and specific heat of both the nuclear and electron–phonon subsystems. I will illustrate with recent results on the heavy-fermion superconductor CeCoIn5, comparing the indications of quantum criticality from specific heat and 1/(T1T). I will also discuss a compact quantum-critical scaling description of the specific heat of quasicrystalline Yb–Au–Al.