With conventional offset printing, books are manufactured in quantities of hundreds, thousands or even millions, and are usually expected to be sold in a year or less.
If sales are slower than expected and the book is a novel, memoir or a collection of poetry, it makes little difference if a book written in 2007 and published in 2008 is purchased in 2020 and finally read in 2030.
But in a fast-changing field in business, technology or even politics or history, a book written just six months ago may be seriously out-of-date. It may contain inaccurate information and bad -- even harmful -- advice, that is presented as current, truthful and useful.
There is not much an author who works with a traditional "trade" publisher can do about obsolete books on the shelves of a distributor or bookseller.
But publishers -- especially self-publishers -- who produce eBooks or use Print-On-Demand for pBooks, have no legitimate excuse not to update books that have become out-of-date.
I'm nearly finished reading a book in a field I know well. It's a POD book with a 2009 copyright, and I expected it to be reasonably up-to-date, and accurate.
Sadly, it has several serious inaccuracies that can mislead readers, causing them to waste a lot of money.
When I questioned the author, he said, "The book was published in 2009 but mostly written in 2008. . . . When I update the book next year [i.e., 2012], I will be making revisions to those chapters."
That's just not good enough. Taking four years to make corrections in a POD book is inexcusable, irresponsible, reprehensible and shows contempt for readers.
(This paragraph is aimed at the usual anonymous snarksters who read my blog posts.) My first book on self-publishing came out in late 2009. It is no longer current (but is not dangerous). The eBook replacement has been on sale for about a month and the new pBook should be on sale in a week or so. Although the 2009 book is still on sale, I have a note posted on Amazon that says, "Note from author: Please buy the newer version" and points out that much has changed since 2009 and lists some of the things that are covered in the 2011 book, but not in the 2009 book.