I don't usually cover actual history books on this blog, because I'm generally more interested in fictionalised versions of the ancient world, though there are many "factual" (to a greater or lesser extent) programmes and books that are undoubtedly designed to be "popular". I'm making an exception for these books though, because they were my first ever exposure to ancient history.
Back when I was in primary school and thought Romans were boring, two new books came out and were advertised to us via the book club the school subscribed to. Several people bought The Terrible Tudors, including me - I was always very interested in the Tudors, especially Henry VIII and his six wives. I enjoyed it a lot, so I started collecting the books (I continued to try to own all of them for years, until eventually I had to give up as the cost of children's books started to skyrocket). The Rotten Romans was the third book to come out, in 1994 (The Awesome Egyptians was released at the same time as The Terrible Tudors, in 1993).
The books consist of lots of different written elements - quizzes, cartoon strips, pretend newspaper articles and diaries, timelines and other bits and pieces - and cartoon illustrations. I loved them, and repeated their jokes ad infinitum (still do - one of my favourites was The 20th Century (published 1996)'s prediction that we would all drown in fridge suits in the year 2000, at least, those of us who survived Mad Treacle Disease). This is where I first learned that Caligula made his favourite horse a senator (which, actually he didn't - Dio Cassius only says that he thought about making his horse a
(Edited to add: It has been pointed out to me that both Dio Cassius and Suetonius write that Caligula intended to make Incitatus a consul, not a senator - see comments. This is entirely true - but I have a feeling The Rotten Romans, I, Claudius or both say 'senator', which is why I always make that mistake. When I can get hold of them, I will return with the answer).
You can see some of the problems with the books from the examples above - there are the sort of inaccuracies you get with broad generalisations, as in the Caligula's horse story, the books rely a lot on 'fun' trivia regardless of likliehood, like the Boudicca story, and they have to be censored for a young audience - those 'friends' were Messalina's lovers. They also focus, as the title suggests, on the gory side of things, on the assumpion that kids love gore, though some children (like me - I used to cry all through assemblies where upsetting stories were told) don't actually like gore or enjoy hearing nasty stories. (Not that I think things aimed at children should be censored or have all the scary stuff taken out, it's only a problem if they're treated as an educational tool and children are forced to endure something that upsets them).
Overall, though, I think the books are a great introduction to history for children. They try to introduce the concept of historical enquiry - I remember one which explained the controversy over the death of Christopher Marlowe - and they get children interested in history. For years, all I knew about the Romans was gleaned from The Rotten Romans. I still enjoy the books and find them hilariously funny, and one of these days, when I win the lottery, I'll collect them all...
The image at the top of the page is the original 1994 book cover, which I have to say, I much prefer. This is the new cover, and apparently there's some new content in this edition as well.