It's 1971: computers are those strange machines that do odd things to Gas bills (Headlines such as Mrs Brown receives £999,999,982.45 Gas Bill were common) or are dark machines dedicated to global domination (See "The Forbin Project" or "The Billion Dollar Brain"). No-one - and I mean no-one - had a computer at home or even works directly with one in the office: mysterious machines indeed.
Then along comes Ladybird books and produces a simple, clear and highly readable book that explains the basics of what a computer does, how it does it and what can go wrong. Illustrated with a picture on every page, it doesn't patronise its audience (assumed to be 8-11 years old) but it doesn't avoid tackling some technical ideas, such as binary arithmetic.
For its time it was a terrific children's book: clear, concise and enjoyable. It is now rather past it, but as an example of how to write a children's book it cannot be bettered. As a final thought - There was a story that in the mid-70's the UK Ministry of Defence ordered 500 copies of this book to educate senior staff - if so, someone chose well.
I still have this book from the 1970's - or an earlier edition of it. I was doing a newly introduced O Level in Computer Science - the teacher handed out a long tome that was the official text book - then said it was probably best for us to all head to WH Smiths to buy a copy of this. The amazon listing popped up when I was looking at the new series of Adult Ladybird books - brought back fond memories - and must of done some good, my O Level may have included state of the art 'punched card' technology, but I have run IT departments for several organisations on the strength of it (and maybe a tiny bit of CPD!)