Evolvable Hardware (EHW) refers to HW design and self-reconfiguration using evolutionary/genetic mechanisms. The paper presents an overview of some key concepts of EHW, describing also a set of selected applications. A fine-grained Field Programmable Transistor Array (FPTA) architecture for reconfigurable hardware is presented as an example of an initial effort toward evolution-oriented devices. Evolutionary experiments in simulations and with a FPTA chip in the loop demonstrate automatic synthesis of electronic circuits. Unconventional circuits, for which there are no textbook design guidelines, are particularly appealing to evolvable hardware. To illustrate this situation, one demonstrates here the evolution of circuits implementing parametrical connectives for fuzzy logics. In addition to synthesizing circuits for new functions, evolvable hardware can be used to preserve existing functions and achieve fault-tolerance, determining circuit configurations that circumvent the faults. In addition, we illustrate with an example how evolution can recover functionality lost due to an increase in temperature. In the particular case of space applications, these characteristics are extremely important for enabling spacecraft to survive harsh environments and to have long life.