Whether you're familiar with the book or its author, it's very likely you've a famous phrase akin to, "If you wish for peace, prepare for war". The source - thoughsomewhat misquoted, as are most famous phrases - is this text, and it was meant in the most sincerest and literal terms.
From the ways to train soldiers to how to battle elephants of war - again, literal - Vegetius gives military advice that helped the Roman Empire become what it did, and it is with some steely hope, but a little sadness, that he writes how it is possible to bring back that glory, if only the troops were as fiercely dediated as they used to be. Much of what he writes of the disinterest new troops show to warfare are strangely familiar with some of the behaviour of modern youth...
What is also interesting is that Vegetius did not actually experience the warfare he writes of greatly. He was more a historian, gathering the information from other texts and collating them. Though little used in the Roman era, it didn't put off his future readers, evidently.
It's hard not to love something that survived to instruct many future generations so aptly, though in itself was a swansong for the greatness of Roman warfare. Asothers note, it was a manual certainly on the shelf of every lord and knight of the middle ages (I state specifically, as reading this era is how I discovered it) who aspired to rise high on the battlefield, and without doubt in the hands of every king (well, maybe not Edward II...). For sure it was carried 'everywhere' by grand Plantagenet Richard the Lionheart, and his father, Henry II. It apparently circulated as essential to life in the time of Charlemagne.
Great little book, giving quite some insight into a last ditch effort to reclaim Rome's former glory, while setting up the rest of Europe to take the mantle.