The stimulation of technological development by scientific discovery is a widely accepted premise. Somewhat less recognized is the inverse relationship, the stimulation of science by technology. Examples of the latter are the advances in thermodynamics following the development of the steam engine by Watt; and the advancement of the understanding of thermionic emission into gases, by Langmuir, following his own invention of the nitrogen-filled electric bulb. In this paper, we discuss several examples of contributions to science at IBM Research which were generated by our technological effort. These are of two types. The first one comprises scientific investigation stimulated by the need to understand some technological problems. Examples are the 'two-dimensional electron gas' investigations inspired by the desire to understand the physical properties of the planar field-effect transistors; or contributions to the theory of magnetism stimulated by the advent of 'magnetic bubbles' as a promising storage medium. The second type of stimulation of science by technology is the creation of new tools for scientific investigation. Examples are advances in electron-beam microscopy, originating from a search for improved microfabrication techniques; or the development of tunable lasers, coming out of a search for new devices, not necessarily with a computer orientation, and finding a wide range of applications in physics, chemistry and biology. Beyond enumerating several examples such as the above, we have made an attempt to identify factors contributing to the cross-fertilization of science and technology. We propose three as among the most important ones: strong interactions among scientists and technologists; novelty of the technology involved; and initiative coupled with a searching attitude for underlying principes and phenomena on the part of the researchers involved. © 1979.