  This review is split into two parts: one on chromospheric line formation in
answer to the frequent question "where is my line formed", and one presenting
state-of-the-art imagery of the chromosphere. In the first part I specifically
treat the formation of the Na D lines, Ca II H & K, and Halpha. In the second I
show DOT, IBIS, VAULT, and TRACE images as evidence that the chromosphere
consists of fibrils of intrinsically different types. The straight-up ones are
hottest. The slanted ones are filled by shocks and likely possess thin
transition sheaths to coronal plasma. The ones hovering horizontally over
"clapotispheric" cell interiors outline magnetic canopies and are buffeted by
shocks, most violently in the quietest regions. In the absence of
integral-field ultraviolet spectrometry, H$\alpha$ remains the principal
chromosphere diagnostic. The required fast-cadence profile-sampling imaging is
an important quest for new telescope technology.
