"A systematic Bible study course". "This course of Bible reading was first issued in 1934 in response to a widespread demand from Christian students and others for a systematic plan which could be used daily. Its aim is to guide the reader through the whole Bible in three years of regular daily study" (from the Preface).
Books can be attributed to "Unknown" when the author or editor (as applicable) is not known and cannot be discovered. If at all possible, list at least one actual author or editor for a book instead of using "Unknown".
Books whose authorship is purposefully withheld should be attributed instead to Anonymous.