Believe It or Not is like Guinness World Records, the author gives you a lot of information about interesting or crazy things people have done. Robert Ripley, the author of the book became a huge star after he founded this book. This book is Non-fiction, the genre is mostly crazy but also a little scary. I think Ripley made this book for humours or knowledgeable thoughts.
I think the author of this book tried to deliver that people can do anything but only if you commit to what you are trying to do. Personally I learned quiet a few things for example, we people can be obsessed to something easily or we can make miniature things. I don't think you would a lot learn from this book, you would probably get to the point of people can do anything but only if you commit to it.
I would give this book a 8, it has weird but also funny short stories. My favorite part of the story is on page 12 where I found out there is a pink lake in Africa, Senegal. I would recommend the for 10-12 year olds who like to read short and interesting "stories".
I hope you will enjoy the book.