A bygone era

In the midst of completing my iTunes U course about 3rd millennium technology I came across the following book that was buried in a dusty old box from our previous office.  I kept it for posterity because, well sometimes that's what you do with books.  Do people keep apps or iBooks for posterity? For purely sentimental reason because the smell and the feel and the patina of the artifact evokes something within you that takes you back to a bygone era?  This is the reason why I rescued this book from pulverization and I share a couple of pictures below:

It took an act of enormous self-discipline to stop myself from uploading another 20 pictures from this book, and equally to resist spending an hour looking up hardware from the era such as the Sinclair ZX-81 - referred to in the book if you look carefully as the Timex Sinclair 1000.
Sigh.