This is the book that I was expecting for along time. As Professor of Surgery I have to read medical textbooks, and I appreciate those concise volumes dedicated to medical students that can help me, then I suppose that this book could be useful to astrophysics too, not only to amateur astronomers like me. The aims of Robinson's book have been successful: to explain the physical processes that cause the stellar spectra with a language understandable. I am very grateful to Robinson that the important concepts are showed repeatedly along the book. He teaches us how the quantum theory explains all spectral mysteries. Starting with the electromagnetic radiation, the black body concept, Robinson expounds in great detail, but very understandable, the electron transition, the energy levels (the famous Ha line), and the consequences when a photon collides with an atom (excitation, ionisation). The quantum numbers are depicted very well with clear diagrams, and how they determine the energy levels and the spectral series. Up to here, it is the atom lab information; but the stellar objects are very complexes: objects with velocity (the famous Doppler effect), and atmospheres with temperature, pressure, and turbulence..., physical processes that cause the broadening of spectral lines. Robinson details the spectral line profiles with examples useful to amateur astronomers. After to expound the absorption lines and the emission lines, Robinson explains the whys the nebulae, with gas that absorb the photons of the central star, have emission lines instead of absorption lines. Robinson use the chapter of accretion disks as pretext of to speak us that amateurs astronomers could performer astrophysical modelling. The book finishes with the exposition of the P Cygni profile, and the world of magnetic field. Robinson has been very clever with this difficult task, the magnetic field, in order to teach the important marks for the amateur. Finally my modest recommendations for those amateurs that would like to start in this field: to read the Tonkin's book "Practical Amateur Spectroscopy", and the course of Aude Peltier "Initiation a la spectographie" (tutorial of astrosurf.com).

Dr. Barneo