As a student of political science, I was always in need of electoral data for the British House of Commons. Until buying this book, Wikipedia's bare and incomplete details had to sufficed but were often lacking in data which was either detailed, old or both.
This book changed all of that. It includes, of course, the basic details regarding vote and seat numbers/percentage for all the major parties in every single general election since 1832 up until the most recent one (at the time of writing) in 2005. It also includes data which would be almost impossible to access readily elsewhere such as the number of spoilt ballots, postal votes, detailed turnout breakdown, specific seat gains/losses, referendum results, polling, electoral irregularities, etc., etc. Specific focus is given to the major parties, regions and elections so that the data can be viewed in any context that may be useful to the reader.
I also get the impression that a lot of the data is secondary, that is the authors themselves have manipulated existing figures in order to calculate interesting new findings such as adjusted electoral turnout percentages and the Tory/Labour vote assuming a 2 party system.
Indeed the detail is, even for university level study, too detailed if anything, but of course that doesn't matter; the clearly-listed contents page and well-formatted book structure means the individual data one desires can easily be found and used. On most pages, there is a good amount of white space between each figure, so rows and columns are unlikely to be muddled. Only on a very small number of pages is the data small and cramped, so those who need glasses when reading will probably get away with not wearing them for the vast majority of this book.
This latest edition has meant the significant price reduction and hence the book is affordable for anybody who needs it. I bought it for this reason to aid my studies and have been very glad that I did so!