We talk of historical developments in surface chemistry of the 1960s and 1970s. With new ultra-high-vacuum chambers now available, chemists began to study the surface structure of metals, oxides, and other salts, plus semiconductors. They discovered surface relaxation and reconstruction. They employed techniques such as electron-diffraction and photoelectron spectroscopy, along with Auger-electron experiments and thermal desorption, and total internal reflection of light--all of which are explained in this episode. We end with a brief discussion of two luminaries of the field, Gabor Somorjai and Gerhard Ertl. My Patreon supporters can download a supplemental sheet to help diagram ideas mentioned.Support the show Support my podcast at https://www.patreon.com/thehistoryofchemistry Tell me how your life relates to chemistry! E-mail me at steve@historyofchem.com Get my book, O Mg! How Chemistry Came to Be, from World Scientific Publishing, https://www.worldscientific.com/worldscibooks/10.1142/12670#t=aboutBook