It's the strangest thing. I've been trying to write a command that gives a player a written book, but the command fails due to minor syntax variations (none of which are supposed to cause an error) without giving an error message. If you leave out a single part of the syntax that is supposed to be included, the command doesn't execute at all (note that this is using command blocks because the command is too big for execution from chat). The strangest part is that the command does not execute if the first line of text in the book does not start with \n, or it gives an error that there is missing syntax. After some playing around, I have found that this holds true for this command regardless of length, so it has something to do with the execution of the command.