"Norton Commando Gold Portfolio" shows on its cover- misleadingly- the dates 1968-1977. If one expects road tests and other publications from exclusively that era, one is surprised to find later ones, right up to February 1987.
Some of the tests are interesting to read, as they give an idea how the motorcycle press of the time perceived the various Commando models. Generally speaking, whilst in the early ones the press is enthusiastic about everything Commando, towards the end the press get very dismissive about it and probably unfairly critizise features that, from todays point of view, were not as bad as they were made at the time.

Everything post-1977 is complete and utter drivel- especially the "Classic Bike" features, which, in typical "Classic Bike" fashion, see every bike they "test" in a too positive light, combined with the fact none of the bikes they test is normally as it left the factory. If Classic Bike test a real lemon which is totally and utterly gutless, this is always attributed to being "in a relatively mild state of tune", "only just put together" etcetc (remember the "4-valve Commando?). If the thing breaks down at every busstop it "has lots of character". These tests the book could have easily done without.

Some tests are a good read. I enjoyed the tests of early production racers, understandably because I have a genuine one and have ridden it on public roads (not recommended) and on the track (recommended). Also, the test of the first Interstate with the infamous Combat engine, KJW375K, which very machine I sold to a German customer in 1980 due to lack of money to hang on to it- and still mourn the fact.

Really, the decision if or if not you want to purchase one of these books is up to you- you will learn little about the Commando, a lot about how journalism works, and if you have a collection of old motorcycle magazines there is a good chance you have most of the tests already.