CHENNAI: Chief Electoral Officer Satyabrata Sahoo on Saturday released a handbook for Lok Sabha elections with reference to Tamil Nadu and Puducherry, published by Press Information Bureau.  The handbook contains information about the Lok Sabha elections since 1951 and comparative graphics and tables which enables one to arrive at how the elections have moved in terms of population, facilities in terms of ballot papers to electronic voting machines, etc.,  The book contains information about how the election system evolved and improved in the country.  E Mariappan, Additional Director-General, PIB, Chennai, told reporters that the handbook will be useful for journalists too.