In general, I would try to avoid prologues or introductions. As was pointed out very nicely by user15261, the reader's interest in the information you give him has not been stirred yet. For another discussion of prologues, see this post about the length of a prologue.
Personal theory: Concerning "information dumps", my personal experience is that the story gets so much more interesting when you do not introduce your set-up from the point of view of an external observer. Take, for example, a fantasy set-up. Obviously, the reader does not know the rules of the world he's being thrown into. Is that a flaw that needs to be remedied? Or can it create suspense? Personally, I like to be treated like a normal citizen of the world I am supposed to experience. Ask yourself: If you read a story about the US, would you like to know how a car works? Probably not. In that sense, I am more than happy to accept some axxioms of the set-up without questioning them to much. Additionally, doing a bit of detective's work can be fun for the reader, because it asks him to comit himself to the story. If the world is well developped and internally consistent, I think it is legit to give the reader the most crucial clues and leave the rest of the figuring-out to him. That way, he can decide himself how much he wants to know about the world and how much time he invests into thinking about it.
Examples: Two neat ways which I enjoyed a lot in this sense can be found in the works of Jonathan Stroud (for example the Lockwood & Co series or the Bartimaeus trilogy) and Susanna Clarke's Jonathan Strange & Mr Norrell. Bartimaeus and Jonathan Strange & Mr Norrell use footnotes to explain their world on the go. The footnotes are usually irrelevant to the story itself, but they flesh out the worlds of the stories and are fun to read. Bartimaeus simply comments on everything and anything that stirs his attention or (more commonly) annoys him, while Clarke provides her readers with fairytales and other elements of the mythology of her world. Nobody forces you, the reader, to read these footnotes. However, if you are interested in the background of the story, the information is there. In Lockwood & Co, on the other hand, a glossary at the end of the book provides you with the information that is taken for granted by the characters of the story but might puzzle the reader. The glossary headline sits in the table of contents of the book, so you definitely note it when you first open the book. It is then, again, your decision whether you read it or jump straight into the story.
In both cases, however, the story itself is independent from this optional information. (In the case of Lockwood & Co, I was actually a bit annoyed by how often the narrator of the story repeated information that is self-evident for herself. Why talk about it then?) If you opt to provide your reader with supplementary material, make sure the story works, even if the reader choses not to read the extra information.
Implementation: Lastly, my personal opinion on the first few scenes of a novel is that they are absolutely crucial. Whether you chose the "slow" or the "fast" beginning user15261 talked about is your decision, but in any case these scenes should set the mood for the story and give the reader some questions that keep him reading. I enjoy the personal approach, that is, when a character stays true to himself and tells you about the things that are one his mind. (My feeling is that this is independent of the type of narrator you choose.) Do not make him say things that are self-evident for him. If you need to provide information: Make it part of the story. Send your character off to school. Introduce a visiting character that doesn't know the rules. (But don't do this too bluntly.) Introduce an event that actually shakes the rules of your world. You're the storyteller. After all, this is what you do all the time: You have a piece of information in mind that you want to convey and craft it into a story. Why not doing the same for the information about your set-up?
A footnote on Introductions: Being a scientist, the word "introduction" has a very well-defined meaning for me. In storytelling, it corresponds to Act I of the Three-Act Structure in the framework of the Hero's Journey. The introduction is not an undirected "info dump", on the contrary: It provides you with the information that you need to understand both the question at the heart of the scientific publication and the significance of the results. It "sets the stage" for the scientific work that is being presented and puts into perspective every single finding. The same is true for a work of fiction. Act I, here, defines what your story will be about and how the reader judges everything that happens in. Take home message: Take good care of your introduction. It's nothing that you would want to mess up.