Ever since the invention of the laser over 60 years ago, scientists have been striving to create an X-ray version of the laser. The X-ray sources that are in widespread use in medicine, security screening, and technology are in essence a more powerful version of the X-ray light-bulb source that Röntgen built in 1895. In the same way that visible lasers can concentrate light energy far better than a light bulb, a directed beam of X-rays could drive revolutionary advances in science and technology. However, until recently, the power levels required to make an x-ray laser prohibited their widespread use. Fortunately, the challenge of creating tabletop x-ray lasers was solved in a surprising way – by the beauty and power of quantum physics. Visible ultrafast lasers can essentially make electrons sing, to create rainbows of x-ray light – from the ultraviolet to soft X-ray wavelengths.