* Fritz Müller (1821-1897): This is the most likely candidate. He was a German zoologist and a pioneer in the field of mimicry. He is known for his work on the "Müllerian mimicry", where two or more unpalatable species evolve to resemble each other, which benefits both species.
* Friedrich Müller (1862-1940): This was a German architect known for his work on functional architecture, often using materials like steel and glass.
To give you the most accurate information about Fritz Müller's writings, please clarify which Fritz Müller you're referring to.
Once you provide more context, I can tell you about his most famous works!