Ebooks are wonderfully convenient and allow book lovers to carry their entire book collections with them.  However,  despite all of the positives of the ebook phenomenon, it has a few quirks too.

While issues like Digital Rights Management (DRM) are the primary irritants which unfairly penalize honest, paying users, another problem related to ebooks is their very availability.  While most new books are available in ebook format (indeed, many are only available as ebooks!), older books are a different proposition.  Books older than a hundred years which are in the public domain are available for free download on Project Gutenberg (gutenberg.org), but older books which were not that old are very difficult to get in the ebook format.  In most cases, there is simply no choice but to order the printed version of the book, if the book is still in print, or order a used book,  often paying outrageous sums of money for the shipping.  I knew of no other option, till I discovered openlibrary.org.

openlibrary.org is a part of the Internet Archive project and it taps into multiple sources and provides you, the user, with:<div>1. Thousands (perhaps millions) of ebooks which are in the public domain; all of the books in Project Gutenberg</div><div>2. Scanned copies of several hard to get non-public domain books. Many of these titles may not be available anywhere else in the digital format. These may be 'borrowed'. You might need an Adobe account (free) to access these. These are much like books you borrow at the local library, only, they auto-magically get returned after a fixed period of time like two weeks.</div><div>3. A growing catalog of every book ever published. ISBNs, status (in print/out of print), where available (which public library) etc .

openlibrary.org is 100% legal.  Just as it is legal for a lending library to lend out books, openlibrary.org lends digital books, when they are available. You can't buy them or keep them forever, but it offers you an opportunity to get to read many books which you might never have been able to find digital versions of.</div>