Those of us who engage in historical research are likely to assume that everyone will know what tests to apply in order to establish the authenticity of a series of historical documents, and will possess the knowledge necessary for the successful application of those tests. The assumption is unwarranted, of course. Rarely will all possible criteria suggest themselves even to highly intelligent persons without historical training, and more rarely still will they possess the specialized knowledge without which the criteria are useless.
In view of this fact it will be worth while at least to itemize the tests which a collection, such as the alleged Lincoln documents published serially in the Atlantic for December 1928, January and February 1929, should pass before its genuineness can be accepted. First come the purely physical criteria: Is the paper of the proper age, and is the ink that of the period in which the documents are supposed to have been written? Next, the soundness of the collection's pedigree, so to speak: Has it come down through a line of well authenticated, reputable owners? Then, if the documents purport to be the work of a well-known character, comes the question of handwriting. Does it resemble that of letters and papers of undoubted genuineness? More intangible, but very important, is the question of general content. Are the sentiments expressed in any given document in harmony with the known views of the person who is supposed to have written it, or even with his general character as established beyond dispute? Finally, do specific incidents mentioned in the challenged documents check with demonstrable historical fact?