This is the story of a genuine hero, one of uncountable many that America produces and, thankfully, continues to produce. Someone said: Freedom isn't free and this is amply demonstrated in this book. The story of one person's dedication to duty is vibrantly told.
There is a bridge, a heavy, strong, and a very capable bridge. Ironically, built by the US Army several years before. It is the only big strong bridge across a river separating North Vietnam from the south.
A formidable armored column from the north is approaching, intending to use this bridge as their avenue to overtake the south. It is somewhat late in the war, and America is pulling out ("Vietnamizing" the war), but there is a lot of pain and agony still to go through. The destruction of this bridge slowed the advance of the northern armies by three years.
The book is written on the detail level and therein lies its fascination. We see that Capt Ripley climbs over barbed wire fences, swings across the under girding of the bridge, and fights this battle from street to foxhole around the little town of Dong Ha (just a few miles from the DMZ). The writing is wonderful and gripping, putting you face-to-face with the action as it unfolds hour by hour.
This book does lack a few essentials. The full context, with appropriate maps, in time and space is missing. Additionally, the reader is sometimes lost (as I was) in the minute details of the action at the bridge. A very local map or two would have helped.
The heroism of Capt Ripley is focused on his action in moving around under the bridge, while under direct small arms and cannon fire. It is difficult for a reader to appreciate this without almost an engineering drawing of the undersides of the bridge. We read of channels, stringers, girders, piers, all three stories above the river. Capt Ripley was swinging, crawling, and hauling explosives. I (and maybe this is the engineer in me coming out) would have loved to see drawings showing the design of the bridge, with little arrows and annotations ('crawled from here to here', 'pulled xx pounds of explosvie across this girder', 'I was here when the rifle bullets came in', 'the tank shell hit here').
Finally, we note the very emotional and wonderful human touches, the radioman, the commander of the South Vietnames unit, the commander's bodyguard, are described very well; their humanity is very apparent, as is their own dedication to their country. While we learn a little about them, more would have been a great addition. Similarly with Capt Ripley's American compatriot, Major Jim Smock (USA, Armor), who was with him at the bridge.
The book is 186 pages long; it could have been twice that and welcome.

In his desperate attempt to blow up the bridge at Dong Ha and keep some 30,000 men and 200 tanks at bay, Ripley endured three hours of direct fire to rig more than 500 pounds of explosives. Handwalking the beams beneath the bridge, crimping detonators with his teeth, and racing the burning fuses back to shore, he saved his comrades from certain death. This earned Ripley the Navy Cross. He is a 1962 graduate of the United States Naval Academy - - yet another fine American produced at Annapolis.