The author of this prefatory note is not named. In the note, the "author" says that all reports in the following "account" (which we read as the novel Dracula) are "exactly contemporary" with the activities mentioned, meaning that memory has not distorted the presentation of the ensuing facts in the case of Count Dracula. The accounts have been collected in this form in order to present, as factually and accurately as possible, a case that, to most, would seem fantastical and impossible to believe.
This section underscores one of the central concerns of the novel—the idea that the recording of events is taking place "exactly" as they happened, and that the recording itself is without error of memory or transcription. This prefatory note will be book-ended by a "postface" at the end of the novel, which asks whether it is ever possible to record events "truthfully, objectively, and accurately."