<p>I'm planning to apply to PhD programs in neuroscience, probably in computational or systems neuroscience. I had a prof for an advanced writing class when I was a freshman (and might take another class with him next term), who is known as quite difficult prof to please, but he loves me, and any recommendation I got from him would probably be golden. And also, being a writing professor, he knows how to write! If I got a rec from him, would it hurt me that he's not in my field or department? Or does that not matter so much as long as I have at least one rec from my department?</p>
<p>I'm not an expert but I think as long as you have at least 2 other strong letters of recommendation from people within your field that you may have possibly done research with you should be okay. It would be better if you took the second class with him so it demonstrates he is still in close contact with you. He would basically serve as a recommender that can vouch for your work ethic and character while the others will vouch for the quality of research and potential in the field.</p>