A very simple and useful device is to have a memorandum-book, so small that it can be easily carried in the pocket, to be used instead of your mind to keep note of any errand or any appointment that you may have. The Standard Diary, less than four inches long and less than two and a half inches wide, is one of the best for this purpose. ...In fact, such diaries as these, in their wide range of information, would seem to be all that one needs in practical life, the only other book that at all approaches them in this respect being unquestionably Webster's Unabridged Dictionary.