  Recent developments in attosecond technology led to tabletop X-ray
spectroscopy in the soft X-ray range, thus uniting the element- and
state-specificity of core-level x-ray absorption spectroscopy with the time
resolution to follow electronic dynamics in real time. We describe recent work
in attosecond technology and investigations into materials such as Si, SiO2,
GaN, Al2O3, Ti, TiO2, enabled by the convergence of these two capabilities. We
showcase the state-of-the-art on isolated attosecond soft x-ray pulses for
x-ray absorption near edge spectroscopy (XANES) to observe the 3d-state
dynamics of the semi-metal TiS2 with attosecond resolution at the Ti L-edge
(460 eV). We describe how the element- and state-specificity at the transition
metal L-edge of the quantum material allows to unambiguously identify how and
where the optical field influences charge carriers. This precision elucidates
that the Ti:3d conduction band states are efficiently photo-doped to a density
of 1.9 x 10^21 cm^-3 and that the light-field induces coherent motion of
intra-band carriers across 38% of the first Brillouin zone. Lastly, we describe
the prospects with such unambiguous real-time observation of carrier dynamics
in specific bonding or anti-bonding states and speculate that such capability
will bring unprecedented opportunities towards an engineered approach for
designer materials with pre-defined properties and efficiency. Examples are
composites of semiconductors and insulators like Si, Ge, SiO2, GaN, BN, quantum
materials like graphene, TMDCs, or high-Tc superconductors like NbN or LaBaCuO.
Exiting are prospects to scrutinize canonical questions in multi-body physics
such as whether the electrons or lattice trigger phase transitions.

Materials Science