One of the main thing that the main character learned during the problems he solved is if you want to help somebody solve a problem, it doesn't have to be a good way or a bad way.You just have to solve the problem that a person asked you. For example,in the story a Sherlock Holmes solves a problem that had to hurt somebody to solve the problem.I know that because a dog bites a person really hard in the story.Then Sherlock Holmes learns that if he want to help somebody, he have to do what is right or do what is have to be done.In the end of the book, he learns that if he had to lie about something to make a person's life better.Additionally the last thing that he learns is Always help people. I rate this book a "9 out of 10" and