Electoral System Design: the New International IDEA Handbook
The choice of electoral system can have a significant impact on the wider political and institutional framework: it is important not to see electoral systems in isolation. Their design and effects are heavily contingent upon other structures within and outside the constitution. Successful electoral system design comes from looking at the framework of political institutions as a whole: changing one part of this framework is likely to cause adjustments in the way other institutions within it work.
The link address is: http://www.idea.int/publications/esd/index.cfm
