Usborne have made the PDF of the Island of Secrets book and many of their other superb computing titles from the same era freely available on their site.
I especially recommend Write Your Own Adventure Programs For Your Microcomputer. That book got my parser adventure game-making ball rolling when I was a teen, resulting in:
- Dungeon of Death (1988-ish)
- Complex (1988-ish)
- The Sword of Evil (1988-ish)
- Dark Arts (1990)
- Demon's Keep (1990)
Then I wrote a few Eamon adventures, then I didn't make any more text adventure games until IFComp 2010.