The latest edition makes use of current technology.
The printed edition is not the definitive edition of the new manual, according to Porter. The content of record for the manual is the online material, where it is always up to date. The digital edition also allows more content than a book can hold and multimedia features. This differs, of course, from the 1899 edition, which had a nice leatherette cover.
"The 19th edition, published in 2011, was to be last one put to paper. In the end, the editors decided to print the 20th edition to accommodate both users who get their medical information online and those who prefer a book," Porter says. The Merck is also available as free apps, Porter notes.