About a decade ago electrospinning was primarily concerned with the preparation of nanofibers from synthetic polymers and to a lower degree from natural polymers targeting predominantly technical applications areas such as textiles and filters as well as medical areas such as tissue engineering and drug delivery. Since then strong progress has been made not only in the understanding and theoretical modeling of the complex processes governing electrospinning and in the strict control of fiber formation by material and operating parameters but also in the design of a broad range of technical spinning devices. These achievements have in turn allowed for an extension of electrospinning towards fiber formation based not only on polymers – of synthetic, biological nature – but also on metals, metal oxides, ceramics, organic/organic, organic/inorganic as well as inorganic/inorganic composite systems. Here not only preparation schemes were investigated but properties and functions of the nanofibers were analyzed and potential applications were evaluated. As far as technical applications are concerned nanofibers composed of such materials can today be designed in a highly controlled way to display specific structural features. They include phase morphology and surface topology as well as unique functions including in particular magnetic, optical, electronic, sensoric, catalytic functions specific for one-dimensional architectures. Significant developments have also been achieved towards the exploitation of such functional nanofibers in applications involving among others fuel cells, lithium ion batteries, solar cell, electronic sensors as well as photocatalysts. One major target is currently the incorporation of such functional nanofibers in micrometer-sized electronic devices or even the construction of such devices purely from nanofibers.