“The Bible of the Reformers” was the Black Book, a massive compendium of all the abuses, electoral, ecclesiastical, legal, which they sought to abolish. 

The edition cited here was the most influential, coming as it did on the eve of the Reform Bill (1832).  For the Black Book was above all a practical document, and its emphasis on the need to have practical as well as equitable representation lies at the root of parliamentary democracy.