The quest for insights into our world represents an ongoing motivation for mankind to investigate and study. Looking back into history, especially the macro- and microworld attracted much attention, and lead over the centuries to various breakthroughs in research tool development, such as in optical instruments. Although these instruments have been quite helpful in studying the large scale world such as space with its various kinds of stars, planets etc., a real revolution in the understanding of the world happened when applied at the microscale: Discovering cells at the basic units of the organisms or bacteria as the orign of certain deseases opened up fully new areas of thinking as well as research. Often the scale of the visualized structures was far away from anything man could control or prepare back at the time of discovery, reducing the scientist to a simple observer of the small world. Optical instrumentation played a key role in this process: For a long time the only accessible microscopic method, it originated and witnessed many breakthroughs. Based on the invention of higher-resolution methods such as electron microscopy and later-on the scanning probe techniques, and the ongoing miniaturization in microelectronics reaching the lower nanometer scale in structure size, a new field dubbed Nanotechnology emerged in the last decades. Dealing with nanoscale structures and their properties, it also lead to a rennaissance of optical studies motivated by the need for characterization of optical and spectroscopic properties of structures and complexes in this size range. Many groups established optical setups for the study of optical phenomenon of nanostructures and at the nanoscale, and nanooptics became a hot field today. Typical subjects of interest, e.g. metal nanoparticles, could so be visualized and studied. Novel fields such as the combination of plasmonics effects with the molecular world leading to molecular plasmonics, emerged.However, often the historical achievements of generations of scientists and engineers are forgotten in today's fast-paced times. Already 100 years ago the scientist Richard Zsigmondy utilized a custom-made instrument, the ultramicroscope developed at the Zeiss company by Siedenbruch, and was able to visualize metal nanoparticles. The work included (and translated) in this volume contained the - to our knowledge - first published color illustration showing the impressive effects of light scattering on metal nanoparticles with a microscopical background. This booklet wants to refresh the memory of the researchers and their achievements by providing access to their historical work that happened a long time ago but nevertheless presented a breakthrough in optical microscopy and paved the way for recent developments in nanoparticle detection and characterization techniques.