CraftBook is for anyone trying to learn a craft, and looking to take the 'two steps back' out of their every step forward.
It is a craftsperson's workbook. It is where you externalize your thoughts, define your challenges, and log your solutions. You haven't truly grasped a concept until you can explain it to yourself--CraftBook forces you to do exactly this, every step of the way. In doing so, you maximize every ounce of effort you pour into your craft.
Learning a new skill can be a tortuous process. You forget what you learned yesterday, and end up solving the same problem three times, praying that your muscle memory kicks in automatically. You lose sight of what you were trying to accomplish, especially when faced with a problem that is really a cluster of problems intertwined. You assume you've mastered a skill when you've barely scratched the surface.
CraftBook is where you put all of your thoughts down--the problem, and all of its relevant questions. CraftBook can turn these questions into search queries, bringing up a library of possible solutions for you to peruse. When you've found a solution, CraftBook gives you space to record it in your own words, while encouraging you to think about how you could've come to that solution on your own. These problem-entries can be organized into daily summaries, where you detail what you did yesterday, what you discovered today, and where you should go tomorrow. And finally, CraftBook can quiz you, bringing you a random problem out of past entries, and forcing you to explain that concept in basic terminology, tesing it based on readability metrics.