Actually, every writer with any experience at all will tell you that the question is not whether or not to infodump.  The answer to that question is automatically yes.  Yes, yes yes.  The need to provide mass quantities of data to the reader is almost universal.  Especially in longer works.  Most especially in longer works laid in milieus that are outside the reader’s common experience.

No, the real question-questions, rather-is how/when/where/how much to infodump?

And as much as I would like to be able to give the One True Answer to those questions, there is no such critter.

If you were to put three authors in a room and asked them one of those questions, you’d get probably get somewhere between five and nine opinions.

Actually, I misspoke.  There is one answer, but it is not an answer.  (And no, I’m not going all zen on you.)  The answer is . . .

It Depends.

Seriously.

That’s the only answer there can be.

Okay, setting aside the foolishness, here’s the hard core.

Yes, as a writer you have to be able to fill the void of ignorance each reader faces when he/she picks up a new work by you.  My experience is that writers attempt to do this in one of three ways.

1.      The Bulk Transfer Method

Wherein the writer attempts to stuff everything the reader might possibly need to know down the reader’s throat at once.  Two common forms of this are:

The dreaded “As you know, Bob…” conversation, in which one character will recount the history of the universe from the Big Bang all the way through to the ultimate death of heat, coincidentally along the way sprinkling the conversation with little nuggets of data that the reader might find useful somewhere around page 397.

The ubiquitous conference, wherein various talking heads sit around a table and explain to each other things that they already know but are needful for the reader’s understanding.

The problem is that, especially when attempted by new writers, these usually result in large indigestible blocks of verbiage sitting right athwart the plot line, and contact with said block all too often bounces the reader right out of his/her reader’s trance.  This is Not A Good Thing.

2.      The Teasing Method

Wherein the writer attempts to provide subtle hints-a word here, a phrase there-expecting the reader to not only read the written page but also the authorial mind, and somehow pull out of the aether the missing context needed to understand what the author is desiring to communicate.

The bad news here is that telepathy doesn’t work any better between authors and readers than it does between husbands and wives (which, based on personal experience, I’d have to say is not at all), and readers quit in frustration.

3.      The Pay As You Go Method

This is the one that most authors eventually develop, where they learn to tell the reader as much as the reader needs to know at that point in the story.  The trick is developing first the awareness of just what out of the entire back story and world building framework the reader needs at just that moment in the narrative; and second, the skill to add that to the narrative in the right spots and the right proportions.

The frustrating thing is that, like a lot of guidelines, we have all seen successful writers produce successful books that ignore them.  Well, just because they can get away with doesn’t mean we can.

Case in point:  two or three years ago I turned in a draft of a longish story to my editor.  Not long thereafter I got a note back:  “You have committed a staff meeting.”  Translation:  I had a ubiquitous conference in my story, and she didn’t like it.  “You know better than that.  Fix it, and I’ll buy the story.”  I attempted to justify what I had done by pointing to a recent novel by a well-known popular author that had a conference scene that ran for page after page after page.  Her response:  “You’re not him.  Fix it.”  I fixed it.

To summarize:  Option 2 just doesn’t work.  Option 1 doesn’t work well . . . except when it does.  Option 3 is preferred, except for those rare occasions when Option 1 is the best way to go.

In other words, It Depends.

Final word:  whatever technique is used to provide information, it can’t be just a static dump of data.  Somehow, in some way, the presentation of the data must advance the story.  If it doesn’t, we’re just building walls instead of roads to the end of the story.