I am a big fan of the VSI series, having become familiar with them whilst studying at University. For anyone engaged in academic study of history, you will be all too aware of how useful it is to have a good overview before commencing detailed study. When studying any issue or time period, it is invaluable to possess an understanding of the broad sweep of events before delving into the details of any one particular event. The Very Short Introductions provide this crucial background information.
I have used many of the VSI series, and the Cold War by McMahon is among the best. The narrative is largely complete, and outlines all of the major Cold War events - certainly in enough detail for any undergraduate paper - providing an interesting veneer of analysis that often raises interesting issues that may have passed you by. The book also features occasional 'boxes' of text that explain headline-making events which are not covered by the broader narrative yet are good to know about, for example the Contra affair is covered this way.
If you are merely interested in acquiring a working understanding of the events of the Cold War, then this is a highly useful book. However, it does not delve into any of the theoretical interpretations of the Cold War, and does very little to explain the shifting strategic paradigms employed by either side. So, although you will be left with a good understanding of the events of the Cold War, further reading is essential if you wish to get to grips with the thinking that motivated shifts from, say, containment to détente, or from New Look asymmetry to Flexible Response symmetry.
In short, the book fulfils its mandate, and serves as an excellent short introduction. I would strongly advise that any student who is new to studying the cold war pick up a copy of this book before he gets started on more detailed studies.