Kindle Unlimited and Libby

The Amazon program called "Kindle Unlimited" has some valuable features in my estimation.   "Kindle" is the Amazon name for their ebooks program.  When people go on a trip or a vacation, they often pack a book they are reading.  Waiting for a train or a plane or sitting in a car while somebody else is driving - times when you might read a book. You might choose to read aloud if others want you to.  Once you download an ebook to your devices, you no longer need to be connected.

A good feature of electronic books is that with an internet connection, you can get them at any time the connection is on.  Another good feature is the weight, which is nearly zero:

How much does an ebook weigh? - thetimes.com

So he worked out how much energy that was in joules and using Einstein's 1905 formula translated that into mass, or the weight of the download. Spelt out the long way it is 0.000000000000000001g, also known as an attogram. The ereader might also grow a little heavier in warm weather, because the machine would absorb more ambient energy or ...

Another feature of the Amazon ebooks is their Kindle Unlimited program.  For books that are in the program, they can be borrowed free and read on one's devices.  Only 20 books can be borrowed at once but it is no trouble to choose one and return it to borrow another.  Millions of books are in the program, which costs about $12 a month.

The app called "Libby" is a similar deal that enables a public library-card holder to borrow ebooks from a library through the air.  It is true that ebooks are popular so a library patron may have a long wait before an ecopy is available.