The acclaimed Oxford Latin Course has been completely revised and restructured in the light of a national survey of Classics teachers. The course is in three parts, each with an accompanying Teacher's Book. Parts 1-111 are built around a narrative detailing the life of Horace, based closely on historical sources, which develops an understanding of the times of Cicero and Augustus.
Continuing from the first book in this series, this book introduces several verb tenses (including passive voice tenses), participles, comparatives and superlatives, and extended uses of the ablative case. Thus, with a year of studying these two books, one can read basic Latin decently well with the help of a dictionary, although there is much more grammar to learn.
The great thing about these books is that each lesson provides Latin passages tailored to the grammar and vocabulary covered thus far, so that the student practices reading and understanding by context. The Appendix in this particular book is an adapted version of a section of Petronius' Satyricon and gives the student a healthy challenge at the end of the course.
The downside to these books (at least the first two) is that the vocabulary taught is probably more useful for reading Latin stories rather than for reading academic texts from medieval philosophy and whatnot. I will have to do a good deal of personal study of vocabulary and rhetoric to get up to that level.
But these books do teach much about Roman culture and history, and so they serve well for classical studies.