The Ten Long Novels
The following list contains the ten longest novels that I have read over my lifetime. Starting in the Nineteen-sixties and continuing to this day I have read an average of about seventy books per year. This has included books of many sizes but the ten longest books I have read range from 981 to 2,281 pages in length. Some of these I have read multiple times, including Proust, Mann, Tolstoy, Rand , and Dickens. There were another half dozen books that just missed the list ranging from 825 to 980 pages. I have excluded "genre" novels thus you will not find The Lord of the Rings or The Foundation Trilogy.
There are two qualities that all of these novels have in common in addition to length: They are all very good (even great) books and I enjoyed reading all of them (or I would not have finished them). Among these novels there are additional aspects worth mentioning: Vikram Seth's A Suitable Boy has the distinction of being the longest novel that is not partitioned into separate volumes. I believe that is a distinction that it still holds. Robert Musil's novel has an additional 600 hundred pages of unfinished material that are not included in the three published volumes. Writing the novel literally killed him.
I am not sure if length is an important measure of the worth of a novel, but I would recommend all of these and hope that you do not hold their length against them.
In Search of Lost Time by Marcel Proust (two volumes, 1913-1927), 2281 pp.
Joseph and His Brothers by Thomas Mann (four volumes, 1933-1943), 1492 pp.
A Suitable Boy by Vikram Seth (1993), 1474 pp.
War and Peace by Leo Tolstoy (1869), 1386 pp.
The Cairo Trilogy by Naguib Mahfouz (three volumes, 1957), 1313 pp.
Les Miserables by Victor Hugo (1862), 1194 pp.
Atlas Shrugged by Ayn Rand (1957), 1168 pp.
The Man Without Qualities by Robert Musil (three volumes, 1951), 1130 pp.
Snopes by William Faulkner (three volumes, 1931-1957), 1065 pp.
Bleak House by Charles Dickens (1853), 989 pp.
(Novels that came close, but did not make the top ten included From the Terrace, Don Quixote, Middlemarch, David Copperfield, An American Tragedy, Tom Jones, and The Way We Live Now.)