Okay kiddo, do you know what a book is? Well, Daniel Paul Schreber was a man who wrote a very important book about his feelings and thoughts called "Memoirs of My Nervous Illness".
Now, Schreber was very sick and he felt like his mind was playing tricks on him. He believed that he was turning into a woman and that he was receiving messages from God. He even thought that his doctor was trying to control him with rays!
But we know that these things aren't real, right? Schreber's brain was just feeling a little confused and he needed help from his doctors to get better.
Doctors read Schreber's book and learned a lot about how sick people's brains work. They even named a type of mental illness after Schreber called "Schreber's Syndrome".
So even though Schreber was really sick, he helped doctors understand how to take care of patients like him. And that, my dear, is why Schreber is so important.