The Hitchhiker's Guide to the Galaxy is a wholly remarkable book.
It looks rather like a largish electronic calculator. It has about a hundred tiny flat press buttons and a screen about four inches square on which any one of a million "pages" could be summoned at a moment's notice. It looks insanely complicated, and this is one of the reasons why the snug plastic cover it fitted into has the words Don't Panic printed on it in large friendly letters. The other reason was that this device is in fact that most remarkable of all books ever to come out of the great publishing corporations of Ursa Minor. The reason why it was published in the form of a micro sub meson electronic component is that if it were printed in normal book form, an interstellar hitch hiker would require several inconveniently large buildings to carry it around in.
It is not an Earth book, and has never been published on Earth.
In fact it was probably the most remarkable book ever to come out of the great publishing houses of Ursa Minor.
Not only is it a wholly remarkable book, it is also a highly successful one-more popular than the Celestial Home Care Omnibus, better selling than Fifty More Things to do in Zero Gravity, and more controversial than Oolon Colluphid's trilogy of philosophical blockbusters Where God Went Wrong, Some More of God's Greatest Mistakes and Who is this God Person Anyway?
In many of the more relaxed civilizations on the Outer Eastern Rim of the Galaxy, the Hitch Hiker's Guide has already supplanted the great Encyclopedia Galactica as the standard repository of all knowledge and wisdom, for though it has many omissions and contains much that is apocryphal, or at least wildly inaccurate, it scores over the older, more pedestrian work in two important respects.
First, it is slightly cheaper; and secondly it has the words DON'T PANIC inscribed in large friendly letters on its cover.