Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Member of the Scottish Parliament (MSP) (Ball Pàrlamaid na h-Alba (BPA) in Gaelic) is the title given to any one of the 129 individuals elected to serve in the Scottish Parliament. MSPs are elected in one of two ways: First past the post constituency MSPs or; Regional additional-member MSPs . 73 are elected as constituency MSPs and 56 are elected as additional members, seven from each of eight regional groups of constituencies. This additional member system produces a form of proportional representation for each region. All MSP positions become simultaneously vacant for elections held on a four year cycle. If a vacancy arises at another time, due to death or resignation, then it may be filled in one of two ways, depending of whether the vacancy is for a first-past-the-post constituency MSP or for an additional-member MSP. A constituency vacancy may be filled by a by-election. An additional-member vacancy may be filled by the next available candidate on the relevant party list.