1. Sommerfeld, A.: Atombau and Spektrallinien, 6. Aufl., Bd. I. Braunschweig 1944. — This is still to be regarded as the most fundamental book on the general theories of spectra. Naturally the treatment of X-ray spectra forms only a comparatively small part of this extensive work. As a good substitute the following book is recommended: Condon, E. U., and H. Shortley: The Theory of Atomic Spectra. Cambridge 1935.
2. Siegbahn, M.: Spektroskopie der Rüntgenstrahlen, 2. Aufl. Berlin 1931. ü The classical work on experimental X-ray spectroscopy. It contains detailed descriptions of all equipment designed before 1931. All the individual wavelength measurements up to that time are tabulated. The book contains a complete bibliography for X-rays up to and including the first part of 1931. In case the reader has not access to a copy of Siegbahn’S book he is referred to: Lindh, A. E.: Röntgenspektroskopie. In Handbuch der Experimentalphysik, Bd. 24, Teil 2. Leipzig 1930.
3. Compton, A. H., and S. K. Allison: X-Rays in Theory and Experiment, 2nd ed., London and New York 1935. ü A very complete and detailed account of the general physics of X-rays forming an excellent complement to the works under number [2]. The theory of the double crystal spectrometer is treated with all essential details.
4. Dirac, P. A. M.: Principles of Quantum Mechanics, 3rd ed. Oxford 1947.
5. Seitz, F.: The Modern Theory of Solids. New York and London 1940. ü This book together with the works 6 to 8 gives the foundations for the application of X-ray spectroscopy to solid state physics.