In a tribute to the contributions of Sir Alan Walsh to atomic spectroscopy, and in particular to his pioneering
efforts in conceiving and developing the technique of atomic absorption spectroscopy, a brief overview is given of
some developments in light sources and detection methods that took place during his leadership of the spectroscopy
group at the CSIRO Division of Chemical Physics, Melbourne, Australia. The topics covered include hollow-cathode
lamps, high-intensity lamps, resonance detectors, selective modulation of resonance lines emitted by hollow-cathode
sources and isotopic analysis