Alpha Readers. These are the most trusted, earliest readers of a work. Alpha Readers are the ones who see the material closest to the point at which it's first out of an author's brain and put on the page. These readers are usually close friends, mentors, and other people the author implicitly trusts to be honest yet supportive, because they see the material at the point where the author is most vulnerable and unsure of what problems the work may have.

Beta Readers. This second set of readers are the ones who see the material after it's been polished up a bit. Beta Readers can be close acquaintance of the author, or they could bring other value to the process. Some authors, for example, recruit voracious readers in the genre or educators who are well versed in the tropes and conventions of that particular kind of writing. Beta Readers are often at the point in the process where the author still needs feedback on the basis of story and character.

ARC Readers. These are the readers that receive Advanced Reader Copies (ARC) of the manuscript. See the Reviewers section below for more information on ARCs.

Developmental Editors. These editors handle the big issues like story, character, and theme. Their job is to look at the work as a whole and help improve the main elements of the work. They'll look for things like whether the character's motivations are consistent from scene to scene, whether the manuscript is well-paced, and if a particular story point works or could be improved.

Copy Editor. These editors handle the actual presentation of the text. Copy editors are the ones that will fix those pesky problems with shifting between present and past tense, or over-using particular phrases, or structuring the length of paragraphs to better pace the read, or helping offer suggestions to punch-up descriptions with more nuanced or effective word choices.

Proofreader. Like copy editors, proofreaders are looking at the text. But whereas copy editors are responsible for correcting and improving the text, a proofreader is typically looking at a manuscript line-by-line, word-by-word, looking for minor technical errors like typos and punctuation errors, as well as anything other editors and readers may have missed such as misspellings, formatting errors, and the like.

Cover Designer. The cover is one of the most important aspects of a book. Most readers heavily rely on the appeal of a cover to decide what they're going to read. Someone who specializes in graphic design will understand not just how to technically put together a cover file, but the really good ones also understand what elements go into a good cover. Some designers even specialize in particular genres or covers for particular types of audiences.

Blurb Writers. One of the most specialized types of writing is the blurb material that goes onto the back cover, inside flap of a dust jacket, product description, etc. A lot of information and appeal needs to be packed into very, very few words, so someone that specializes in ad copy or other copywriting is often relied upon to come up with effective, engaging copy to catch the attention of readers.

Street Team. A street team is a catch-all term for the team of people that can be relied upon to promote your work to potential readers. A street team might include people who are particularly adept at reaching large audience on social media platforms, or aren't shy about reaching out to complete strangers who might have an interest in reading your kind of work, or might even be people with connections or a willingness help with ancillary types of promotion like book signings, convention appearances, radio or podcast interviews, etc.

ARC Reviewers. As mentioned above, ARCs are Advanced Reader Copies of books. These are book copies handed out prior to the release of a book for the purposes of having reviews, talking points, etc. prepared for the book's release. ARC Readers can often be part of an author's street team or book critics; basically anyone that would have a reason to want to have remarks or a review ready to go as soon as the book is out for sale so that they have time to read it and think it through.

Post-Release Reviewers. These are any reviewers that provide feedback after the release of the book. With the rise of online marketplaces like Amazon and content sites like Goodreads, Bookbub, etc., there's a significant demand for feedback that other users can evaluate before making a purchasing decision. With so many places needing reviews to populate their product pages, reviews are often welcome at any time,
even well after the initial release.