Abstract Let’s make things smaller Kees FLIPSE Technical University Eindhoven, Holland "Make it small" is a technological edict that has changed the world. The development of microelectronics, first the transistor and then the aggregation of transistors into microprocessors, memory chips and controllers, has brought a wealth of machines that manipulate information by streaming electrons through silicon. The idea of making "nanostructures" that comprise just one or a "few" atoms has great appeal, both as a scientific challenge and for practical reasons. However, the investigative tools and level of understanding of basic nanoscale phenomena are now only rudimentary. For the promise of nanotechnology to be realized, much more fundamental scientific knowledge is needed, including understanding of molecular self-organisation, how to construct quantum devices, and how complex nanostructure systems operate and what new and novel quantum properties will be enabled by nanostructures, especially at room temperatures. In these lectures I will discuss a few examples: how a quantum property at low temperature can be tuned on a nanoscale, how changes in physical properties due to nanosize effects can be realized and the role of scanning probe techniques in manipulating nanoparticles with the prospect to build molecular nanostructures. For the last subject, experience in manipulating more macroscopic objects is to someone's advantage.