Fortifications of Gibraltar was a evolution of development that took nearly a thousand years to complete. Starting off with a Muslim fort and ending with a British fortress, the story told in this book proves to be interesting and informative. Both authors were born and probably rise in Gibraltar and the book reflects their intimate knowledge of the subject at hand. The book comes well illustrated with drawing, plans and photos of the fortress superstructures as they developed over continual period of time. The book also go into the history of Gibraltar and it is not rare feat that this is one of the highly contested locations in European military history.
If there is a weak point to this book, it is not as well written as it should be. The two authors tried to jam much information as possible in this short book but by doing so, it loses some clarity to what they are trying to inform the readers. A good example is on page 44 when they are talking about the dry-docks and the book uses the acronym "HWOST" without explaining to the readers this means "High Water of Ordinary Spring Tide", an average between high and low tides. Now I knew what it meant but I can tell you one thing, most general readers got no clue.
It should be noted that this book is a perfect companion to Osprey Campaign book #172, Gibraltar 1779-83 by Rene Chartrand. Although a well written book, this book was criticized for not covering the British fortifications of Gibraltar in any sort of details. Maybe Osprey told Rene Chartrand that he didn't have to cover the fortifications since there will be a book on it coming out later.
But overall, this book come recommended because it tell a great history of this near fable fortress that has been part of the great European struggles of the past several hundred years of history. And it does help travelers gain certain insights of history behind the mute walls, tunnels and bastiona that once held the key to naval mastery of this region.