Block quotes in novels are problematic. You know how it goes; you have a character who has received a letter. You want the reader to know what is in the letter and it is too long to put between quote marks, so you drop down, adjust the margins of the paragraph and include the text of the letter. Or maybe the character has written something and you think the reader needs to see it.
Now, here’s the problem. While you have thought out the content of the block quote with much care, the reader skims through it. Even with adequate introduction, readers tend to see block quotes as reference material. We will only read it in detail if we determine we need it.
We might have a tendency to think that by including the full text of a letter or some other type of writing we are showing the reader the contents. This is inaccurate. Essentially, a block quote is an info dump. Info dumps are always a problem when they are not handled well. The longer the quote, the worse it becomes.
To be of value, a block quote needs to be short and/or have sufficient entertainment value in its own right. Some novels are nothing more than letters, meaning the novel is one big block quote, but because the letters tell a story, the author is able to pull it off.
Block quotes kill the action of a story. Ask yourself what your characters are doing while your reader is reading the block quote. In most cases, the characters are just sitting there, waiting for the reader to finish. We can solve that by allowing the characters to deliver the content of the block quote. We must be careful, however. What we want is for the character to show how he is moved by the information, not just repeat it for our eyes.