The following is the first and second sentences of one of my favorite (and fairly popular) fantasy books encoded in a cipher I created a few years ago. I'm quite certain it's breakable, but hints/more sample text may be needed to solve it. Partial solutions are welcome. Good luck!
Bonus if you can determine the book's title from its first couple sentences.
Hint 1: (and this is a big one!)
This cipher uses two 5x5 Polybius grids of my own creation. See here for a sample grid. One of them is used somewhat rarely in this text, but it is QUITE obvious when.
As hinted at before, one Polybius grid is used for encrypting letters, and another is used for spaces and punctuation. The second grid results in UPPERCASE letters, while the first results in the more common lowercase letters. The main challenge that remains is to determine how the coordinates of the grids work.
You may notice that different letters are represented by different combinations of symbols throughout the text - which is correct. However, the available letter combinations do not change. What I mean by this is that my options for giving the grid coordinates of an "E" (for example) are the same throughout the puzzle and do not change over time.
In a letter (for example, "E") the second coordinate is always one of the following letters: afkpuz. What is the relationship between these letters? Check yourself by looking at the letters that can be found in the first coordinate of that letter: ejoty