Write a tiny book to sell a huge amount of books (probably not going to happen)
Write a tiny book to become a best seller in some obscure category (probably will happen but completely meaningless)
◉ Write a tiny book to make a small dent in a BIG world (and build your brand and business in the process)

Also note - you can also write a tiny book to make a BIG dent in a small world (e.g. - in your own niche, market, vertical, industry or even local community, which is an analog to #3 😄