One who reads habitually
bookworm, bibliophile, editor, book reviewer, literary critic, proofreader, editorial assistant, scholar, bibliomaniac, person of learning, savant, walking encyclopedia*; see also bibliophile.
One who makes a profession of reading aloud
lecturer, announcer, elocutionist, reciter, rhetorician, soliloquist, monologist, diseur, diseuse (both French), lector, instructor; see also announcer.
Anyone admitted to a library
library patron, user, browser, research worker, scholar, grind*; see also student.
A book intended for the study of reading
primer, storybook, graded text, companion volume, selected readings, anthology, collection, omnibus, models; see also book 1, collection 2, text 1.
A grader of papers
teaching assistant, T.A., lab assistant, professor; see teacher 1, 2.