A manuscript of the Six Cello Suites in the handwriting of Johann Sebastian Bach has never been found. All that is known to exist from the 18th Century are four manuscripts of the Cello Suites, in the handwriting of a number of scribes (more than four); some of theses scribes, such as Johann Peter Kellner, are known and some are anonymous. These ‘four sources’, as they are commonly known, have been used, in the absence of any supposed missing manuscript of Johann Sebastian Bach, to produce the very many printed editions of the Cello Suites that have been published since the first half of the 19th Century. Mainly because of the wide range of conflicting editorial approaches and decisions that have been made in each new edition, argument continually surrounds both the interpretation of the Cello Suites, and the filiations of the ‘four sources’ to each other. Such disagreement, particularly regarding the interpretation of the works, raises many questions about the Cello Suites. Although the titlepages of both the manuscripts from the 1720s state that the Cello Suites were composed by Johann Sebastian Bach, it is possible that they were not, in fact, written by him. This issue forms the main focus of this thesis. To seek an answer to this question of authorship, and to assist in the investigation of the scribal attributions, both of the Cello Suites and other manuscripts, as well as investigating the filiations of the ‘four sources’, the scientific principles and techniques of Forensic Document Examination have been invoked. This is, as far as the author is aware, the first time that such a scientific methodology has been applied in the context of manuscript studies. This thesis presents the findings of that Forensic Document Examination, in tandem with the results of the application of more conventional musicological techniques of authentication and dating of manuscripts. The conclusions drawn from the investigation challenge the traditional view of who the scribes of a number of manuscripts were, and show that there is valid reason to question the authorship of the Cello Suites, and indeed other works normally ascribed to Johann Sebastian Bach.