Reddit reviews A Traveller's History of Italy

Since it looks like you're interested in some general overviews, I'm going to recommend books that give just that. If you're looking for books that go more in depth on Roman topics, I'm more than happy to supply some.

For a brief introduction to Italian history in general, I would recommend Valerio Lintner's
[A Travelers History of Italy]
(http://www.amazon.com/gp/aw/review/1566565219/R1B2MURVDQWPAT/ref=mw_dp_cr?cursor=2&qid=1407607391&sort=rd&sr=8-1). This offers a great overview of Italian history for someone with little exposure to the topic. It will show you plenty of topics you might want to investigate further.

As general overviews of Roman history (survey-level books that provide a contexualized narrative of Roman history), I'm going to recommend two books. [The Romans: From Village to Empire: A History of Rome from Earliest Times to the End of the Western Empire] (http://www.amazon.com/gp/aw/d/0199730571/ref=mp_s_a_1_1?qid=1407608174&sr=8-1&pi=SY200_QL40), by Mary Boatwright and others, and [Ancient Rome: A Military and Political History] (http://www.amazon.com/gp/aw/d/0521711495/ref=mp_s_a_1_1?qid=1407608616&sr=8-1), by Christopher Mackay.
Boatwright's book provides an excellent in-depth overview of the general trends of Roman history, from the origins of the city of Rome itself until Late Antiquity. Though focusing on the political development of the Roman state, there are decent introductions to social and cultural history of the Empire. As the title implies, Mackay's work presents a survey-level overview of the political and military history of Rome, with emphasis placed on the Republic and Principate.

The best introduction to the history and workings of the Roman military is [The Complete Roman Army] (http://www.amazon.com/gp/aw/d/0500288992/ref=mp_s_a_1_1?qid=1407609072&sr=8-1&pi=SY200_QL40) by Adrian Goldsworthy. Goldsworthy is one of the leading Roman military scholars, and provides an incredibly readable yet detailed overview of the Roman army. Seriously, if you read only one book on the Roman military (but please don't!) read this.

While much more academic than the other books I've recommended, Arthur Eckstein's [Mediterranean Anarchy, Interstate War, and the Rise of Rome] (http://www.amazon.com/gp/aw/d/0520259920/ref=mp_s_a_1_1?qid=1407610158&sr=8-1) is the preeminent text on the rise of Rome. Using ideas from the modern Realist school of international relations, Eckstein argues that Rome became preeminent in the Mediterranean not because they were "tougher" than other states, but rather because they more effectively understood and exploited the power dynamics of the Mediterranean world. This is probably not the easiest book for someone just being introduced to Roman history, but if you can get through it it'll be worth it.

Since you mention Venice, I have a book in mind that might be useful, but I'm blanking on the title. I'll get back to you if I can find it ( I'm on mobile right now). I hope you find these titles useful, and if you need any other recommendations please let me know!