Raising books from the dead

We recently moved house and I had to move the 3,000-odd books in my library, a total of over 75 boxes full. This was not fun. I’m now seriously trying to trim down my book collection (yes, I tried to do this before we moved, but didn’t succeed too well, so now I’m getting serious).
The difficulty, of course, is trying to decide what books I am prepared to part with. I do love well-designed hardcover books, but the paperbacks I own are definitely a target. Some of these paperbacks are forty or more years old, and many are not in great condition. So I’m going through them ruthlessly.
Here is where e-books can be a real boon. If I really want to retain the ability to re-read a particular book, but want to get rid of my current poor-quality paperback, I go looking for an electronic version. If I can find an e-book version on sale at a reasonable price then I’m prepared to pay for it and divest myself of the physical copy. In many cases I can find free e-book versions (for example, all of my Joseph Conrad novels, most of Dorothy Sayers, all of Dickens, Wilkie Collins, Conan Doyle etc, are out of copyright and are readily available as e-books from Gutenberg.org or other sources).
But there are a few books that I can’t locate as e-books (or at least, not legally). Extreme measures might have to be taken!
A case in point: a very old paperback copy of Poul Anderson’s Guardians of Time, which some time in the past had been cheaply bound. I think I bought it second-hand, in this bound condition, many a long year ago. It was now literally falling apart, with the paper oxidized to a light brown color. So I decided to try out my new Epson V330 scanner, which came with a nice OCR program called ABBYY Fine Reader.
The result is shown above. It was a fairly tedious exercise to scan each double-page spread, but it was eventually done. The ABBYY Fine Reader did a remarkably good job in converting the scans into text. I turned the raw text into a first-draft epub e-book using the excellent free Sigil program, transferred it to iBooks on my iPad and read through it, enjoying the story, but also highlighting bits where the OCR hadn’t quite worked correctly, which I subsequently went back and fixed. Result, one resurrected book.
Now my question is, was this legal or ethical?
Here’s my case for the defense: The original book is out of print, so I couldn’t buy another physical copy. I had paid for my original physical copy of the book, and I was not going to sell or even give away that copy (in fact, it went into the recycling bin). I am not going to give away or sell the electronic copy. So at the end of the day, one (physical) copy of the book was destroyed, and a new (electronic) copy was born. I’m left, as I was, with one copy of the book. This may not be strictly legal, but I reckon it is definitely ethical.
I don’t expect that I will be transferring many of my books in this way – the whole OCR exercise is very tedious – but it’s useful to have in reserve when there is no other (affordable) way of retaining the words of a book whose physical copy is beyond redemption.

