Oxford's Dictionary of National Biography provides a detailed account of Eliot's life and work, including information on her family, the contemporary reception of her writing, her legacy, and a list of standard sources to consult for further reading.
The University of Iowa's Main Library holds these works of biography of George Eliot:
George Eliot: a Life by Rosemary Ashton (Penguin, 1996)
George Eliot, Voice of a Century by Frederick R. Karl (W. W. Norton, 1995)
George Eliot: the Emergent Self by Ruby Redinger (Knopf, 1975)
Marian: the Life of George Eliot by Simon Dewes (Haskell House, 1974)
George Eliot: a Biography by Gordon Haight (Oxford University Press, 1968)
You might also be interested in biographies of her partner, George Henry Lewes. His entry in the Oxford Dictionary of National Biography is here, and David Williams's biography of him is Mr. George Eliot: a Biography of George Henry Lewes (1983)
Oxford University Press is the publisher of the definitive, scholarly, and critial edition of Jane Austen's novels. Each volume contains the text, with an introduction giving a full publishing history of the work, together with explanatory notes and textual apparatus that records variant readings. The edition is not yet complete, as not all of Eliot's works have appeared in it. The Main Libray holds the following volumes in this edition:
Adam Bede (ed. Carol A. Martin)
Daniel Deronda (ed. Graham Handley)
Felix Holt, the Radical (ed. Fred C. Thomson)
The Mill on the Floss (ed. Gordon S. Haight)
Romola (ed. Andrew Brown)
Scenes of Clerical Life (ed. Thomas A. Noble)
'Quarry for Middlemarch' Notebook, digitized item held at the Houghton Library, Harvard
George Eliots Middlemarch Notebooks, a Transcription (ed. John Clark Pratt & Viktor A. Neufeldt)
Selected pages of the manuscript for 'The Mill on the Floss', digitized, held by the British Library
A Writer's Notebook, 1854-79, and Uncollected Writings (ed. Joseph Weisenfarth)
The Journals of George Eliot (ed. Margeret Harris & Judith Johnston)
MLA International Bibliography (MLAB) is a subject index for books, chapters in books, and articles published on modern languages, literatures, folklore, and linguistics. It is produced by the Modern Language Association (MLA), an organization dedicated to the study and teaching of language and literature. The electronic version of the Bibliography dates back to 1925 and contains over 2 million citations from more than 4,400 periodicals (including peer-reviewed e-journals) and 1,000 book publishers.
Annual Bibliography of English language and Literature (ABELL) contains 880,000 records, covering monographs, periodical articles, critical editions of literary works, book reviews and collections of essays published anywhere in the world from 1920 onwards.
The George Eliot Review is a peer-reviewed journal devoted to the study of George Eliot. Search here to find recent, high-quality scholarship in the field of Eliot studies. Published by the George Eliot Fellowship.