**1. Introduction**

Microscope is derived from the Greek words mikros (small) and Skopeo (look at) [1]. It arose from the need to see and interpret objects at the micro and later nano levels that humanity could not see with the naked eye. From past to present, human beings need to see what is far from them closely. Technological developments and the advancement of the scientific world should shed light on these demands [2, 3]. The scanning electron microscope (SEM), which has made a great contribution to the development of the micro world view, has become a masterpiece in this regard. Just as a kitchen cannot be thought of without a knife, it is unthinkable that we can understand micro and nano structures without enlarging them, especially in metallurgy and micro biology [3, 4]. It makes a great contribution to the examination of wet and dry structures in their natural state, especially in biological samples [2, 5]. For this reason, SEM has become a basic need. Today, this instrument, which is the basis for scientific research, has two types as optical and electron. Optical microscopes use a radiation source, while electron microscopes use an electron source. While optical microscopes were sufficient up to a certain level, they were insufficient for high magnification needs [4, 6]. For this reason, electron microscopes were needed and developed to meet the need for higher magnification. In this part of our book, the historical development, general features and usage areas of SEM will be discussed.
