Start with high-confidence spectroscopy books, then narrow by subgenre or adjacent topics.
Quantum Chemistry and Spectroscopy
Thomas Engel
Radiation Detection and Measurement
Glenn F. Knoll
Spectrometric Identification of Organic Compounds
Robert M. Silverstein, Francis X. Webster
Secondary Ion Mass Spectrometry and Its Application to Materials Science
Sarah Fearn, Alexander Shard
Analytical Techniques in Biochemistry
Mahin Basha
Spectroscopy
Mark F. Vitha
Analytical Chemistry
Bryan M. Ham, Aihui MaHam
Introduction to Spectroscopy
Donald Pavia, Gary Lampman
Surface and Interface Analysis
Seong H. Kim
X-ray Photoelectron Spectroscopy
Paul van der Heide
Spectroscopic Properties of Inorganic and Organometallic Compounds
Richard Douthwaite, Simon Duckett
Spectroscopic Methods in Organic Chemistry
Ian Fleming, Dudley Williams
Computational Chemistry Methods
Ponnadurai Ramasami
Mass Spectrometry
Jürgen H Gross
Inorganic Experiments
J. Derek Woollins
Structure Determination of Organic Compounds
Ernö Pretsch, Philippe Bühlmann