Everest, Kelvin, Coleridge's secret ministry: the context of the conversation poems, 1795-1798 (Hassocks, Sussex : Harvester Press, 1979). [see summary]
Fulford, Tim, Coleridge's Figurative language (Basingstoke : Macmillan, 1991).
Hill, John Spencer, A Coleridge companion (Basingstoke: Macmillan, 1983). Chapter on "Frost at Midnight" (remote link: the whole book is on the web).
House, Humphry, Coleridge (London, R. Hart-Davis, 1953).
Langbaum, Robert, The poetry of experience: The dramatic monologue in modern literary experiences (New York: Random House, 1957).
Magnuson, Paul, Coleridge and Wordsworth: A lyrical dialogue (Princeton, NJ: Princeton University Press, 1988).
Parker, Reeve, Coleridge's meditative art (Ithaca, Cornell University Press, 1975). [see summary]
Plug, Jan, The rhetoric of secrecy: Figures of the self in 'Frost at Midnight.' In T. Fulford and M. D. Paley, Eds., Coleridge's visionary languages: Essays in honour of John Beer, pp. 27-39 (Woodbridge, Suffolk: D. S. Brewer, 1993).
Stillinger, Jack, Coleridge and textual instability : the multiple versions of the major poems (New York : Oxford University Press, 1994).
Wheeler, Kathleen M., The creative mind in Coleridge's poetry (London : Heinemann, 1981). [see summary]
Watson, George, Coleridge, Samuel Taylor, 1772-1834 (London, Routledge & K. Paul, 1966).
Holstein, Michael E., Poet into priest: A reading of Coleridge's 'Conversation Poems,' University of Toronto Quarterly, 48 (1979), 209-225.
Magnuson, Paul, The dead calm in the Conversation Poems, The Wordsworth Circle, 3 (1972), 53-60.
Magnuson, Paul, The Politics of 'Frost at Midnight,' The Wordsworth Circle, 22 (1991), 3-11. [see summary]
Miall, David S., The displacement of emotions: The case of 'Frost at Midnight,' The Wordsworth Circle, 20 (1989), 97-102.