The Smallest Book in the World

It is very likely that it is the "Almanac of the Year 1837", which belongs to a singer of the Elberfeld Opera, in Germany, and which measures 9 millimeters by 1 centimeter and a half.
On the other hand, Mr. W.-H. Martin, an American collector, has amused himself by bringing together numerous documents, illustrations and newspaper articles, in a collection of cuttings which is probably the largest in the world. It measures, in fact, 6 meters high by 6 meters wide and is 70 centimeters thick. Mr. Martin is on page 54.
It must not be very practical to do research in it...