Even today we instruct juries that they may believe all, part, or none of a witness's testimony. Lawyers are held to no different standards in their use of witnesses at trial except lawyers may not offer a witness whose testimony the lawyer believes would commit a fraud upon the court. Lincoln never placed this witness on the stand to elicit any testimony other than what the witness stated to be the truth. Thus the claim that Lincoln "suborned perjury" is naive and insulting. For all that, I enjoyed the underlying research, and the author's exposition of it. It does strike me that consultation with an attorney would have vastly improved the history and dampened the sensationalism.