Booth, Stephen, An Essay on Shakespeare's Sonnets, New Haven, CT:Yale University Press, 1969.

Booth's academic study of the structure of the sonnets considers minute details that most readers disregard, such as chapters on "Rhetorical Patterns," "Phonetic Structure," etc. This is a difficult but useful work.

Greene, Thomas M., "Pitiful Thrivers: Failed Husbandry in Shakespeare's Sonnets," mModern Critical Interpretations: William Shakespeare's Sonnets, edited by Harold Bloom, New York: Chelsea House Publishers, 1987, pp. 75-92.

Greene examines a sense of inadequacy that shows throughout Shakespeare's poetry.

Ramsey, Paul, The Fickle Glass: A Study of Shakespeare's Sonnets, New York: AMS Press, 1979.

Ramsey's scholarly work is careful and thoughtful, but it might be a little complex for some readers.

Shakespeare, William, The Riddle of Shakespeare's Sonnets, New York: Basic Book Publishers, 1962.

Six notable critics—Northrop Frye, Edward Hubler, Leslie Fiedler, Stephen Spender, R. P. Blackmur, and Oscar Wilde—look for...