For clarification, I am talking about novel submissions to literary agents. I've done research and have read many different things. Some say it is a courtesy not to do simultaneous submissions as it is annoying for an agent to get excited over a query just to discover it has already been scooped up. Others say that with the long amount of time it takes for agents to get back to people, it doesn't make sense to only do one at a time. I know that some agents will specify their preferences, but I wanted to clarify the 'unwritten protocol' for when this is unspecified. Not okay to send to multiple agents? If so, what are best practices? Okay if done at a moderate pace (3-4 at a time or so)? Also, I have a question more specific to my situation. As mentioned in another thread, I just submitted to a well-established agent, referred to her by her colleague/friend. This is my first submission ever (I didn't do the video, thank you guys for the advice!), so now that I have a query/cover letter template ready for my novel, there is a strong urge to send to more! In this case, since I was referred AND the mutual friend has informed her that I will be sending something, should I wait a few weeks until I start sending to others? I have no way of knowing how likely she is to respond, but at the same time maybe this situation calls for extra courtesy on my part because she might be more inclined to read my manuscript because of the referral?