Four stars.  It's a decent collection, definitely a good starting point for anyone looking to explore ChatGPT's capabilities.  There are some real gems in here that have given me some fantastic results.  However, a fair number of the prompts are pretty basic or repetitive, and I found myself skipping over quite a few.  The organization could also be improved; a better search function would have been helpful.  Overall, it's a worthwhile purchase if you're new to prompt engineering, but don't expect miracles.