Electrical motors and generators, small and large, serve us daily in numerous ways. The interesting development of these important, but often anonymous, machines is illustrated by four selected examples. With Sweden as platform, the author describes the long evolution of induction motors, the industry's no. 1 workhorse. The partly dramatic development of large turbogenerators for nuclear power plants is covered comprehensively. An overview and analysis of electrical machines for hybrid vehicles is included as example on vital recent development. Another case is a unique invention of large machines with voltages above 100 kV. Introductory chapters containing early history and basic electrical machine technology complement the detailed parts. The book is a piece of history of technology presenting both the product and process development, but it also contains reviews of the industrial backgrounds and strategic contexts. Several comparisons are made, and the book includes analyses of factors of importance for the development. Originally, it was written as a PhD thesis at the Royal Institute of Technology in Stockholm.