For the Bible Challenge in November we are reading the books of Acts and Revelation. The reason we are reading these two books together is that they are the only two books in the New Testament that aren't either a Gospel (that is a story of the life and teaching of Jesus) or an epistle (that is a letter to someone or some community).
Acts is the second part of the book of Luke. It was written by the same author as the Gospel of Luke and to the same audience. Luke was probably a student of Paul and is believed to have traveled with him on his third missionary journey which took them around what is today north Africa, Turkey, Greece and Grecian islands from 52 - 57 CE. Acts was written about 30 years after that journey - between 80 - 85 CE and recounts the story of the early church beginning with the Ascension of Jesus and Pentecost and through Paul's journeys. Acts is written to the same audience as the Gospel of Luke, that is Gentile Christians living in the cosmopolitan areas of what is today Turkey and Greece. The goal of the book is to use the story of the earliest days of Christianity to strengthen the faith of readers and hearers and to instruct them in how to live their faith.
Revelation is an entirely different kind of book. Revelation is a part of the books known as the Johanine corpus, that is books written by John (or by someone closely connected with John). The other books in that corpus are the Gospel of John and the epistles known as 1, 2 & 3 John. The Johanine community were, as far as we know, committed Christians and the writings, including revelation, are more focused on exploring theology more deeply than teaching the basics of the faith. Revelation is an example of what is known as apocalyptic literature. This is a kind of writing that was common from about 250 BCE until about 200 CE. The common thread in this kind of literature is a negative view of the world and hope for salvation either in a new world or in a new life.
Revelation was probably written in the 80's or 90's CE when the Roman Emperor was requiring his subjects to address him as Lord and God and to worship his image. It is likely that Revelation was, at least in part, written to give Christians both hope and instruction in dealing with the political situation they were facing, but by setting it as a story about the end of the world, made it safer to distribute and pass around.