The title's a bit of a mouthful, but happily the book itself is a tasty treat. It covers the period (roughly) from 150BC to 100BC, focusing primarily on a number of wars Rome had at this time and the subsequent rise to prominence and glory of Caius Marius.
This is a period I'm very unfamiliar with, and it was an enlightening and enjoyable read. The author did a very good job of informing the reader where sources were sparse (which, sadly, is quite often) and when they were thought unreliable or to differ with one another. Despite this fuzziness in certain areas the general shape of the conflicts and, to a lesser extent, the political shenanigans in Rome are apparent and interesting.
This later Republican period was one of expansion for Rome, but it was also a difficult time. They did get entangled in difficult wars and suffered quite a number of reverses. However, not unlike in the Second Punic War, the fundamental strength of the Roman political and military machine enabled it to shrug off as flesh wounds injuries that other nation's would have considered deathblows.
It also relates the dominance that the Metelli family (of whom I'd never heard) during this period, with whom Marius was sometimes friendly and sometimes not.
The battles are described in as much detail as possible but due to the lack of sources this is often conjecture or requires certain gaps to be filled with speculation. Whilst unfortunate, the general picture can still be made out.
There are also a number of appendices which cover related matters of interest which are fairly brief but don't fit naturally into the main body of the book.
I thoroughly enjoyed The Crisis of Rome, which also has a nice bibliography for those interested in the period covered and wanting further reading. The sparseness of sources can sometimes be frustrating, but (unlike one review I read) it's entirely unfair to blame the author or criticise the work because Livy's books haven't survived two millennia entirely intact. It's a good work that weaves together the domestic political situation with the overseas military adventures of Rome and provides an easy-to-read and enjoyable overview of a relatively unknown period.