I’m reading page 108 of “Theodore Rex (Theodore Roosevelt Series Book 2),” by Edmund Morris (Amazon link, commission earned).

Also, on page 126:

His “beach book” for the season was Nicolay and Hay’s Abraham Lincoln: A History, in ten volumes. Unfazed, he read it straight through, along with his usual supply of dime novels and periodicals.

You can put those 10 volumes in your Kindle for $2.99. Over 4,000 pages.

There’s also this in the first volume of Morris’s trilogy about TR, describing the extent of his reading:

As quietness settles down over the Presidential apartments, Roosevelt and his wife will sit by the fire in the Prince of Wales Room and read to each other. At about ten o’clock the First Lady will rise and kiss her husband good night. He will continue to read in the light of a student lamp, peering through his one good eye (the other is almost blind) at the book held inches from his nose, flicking over the pages at a rate of two or three a minute. This is the time of the day he loves best. 

“Reading with me is a disease.” He succumbs to it so totally… that he cannot hear his own name being spoken. Nothing short of a thump on the back will regain his attention. Asked to summarize the book he has been leafing through with such apparent haste, he will do so in minute detail, often quoting the actual text. The President manages to get through at least one book a day even when he is busy. Owen Wister has lent him a book shortly before a full evening’s entertainment at the White House, and been astonished to hear a complete review of it over breakfast. “Somewhere between six one evening and eight-thirty next morning, beside his dressing and his dinner and his guests and his sleep, he had read a volume of three-hundred-and-odd pages, and missed nothing of significance that it contained.” 

On evenings like this, when he has no official entertaining to do, Roosevelt will read two or three books entire. His appetite for titles is omnivorous and insatiable, ranging from  the Histories of Thucydides to the Tales of Uncle Remus. Reading, as he has explained to Trevelyan, is for him the purest imaginative therapy. In [1906] alone, Roosevelt has devoured all the novels of Trollope, the complete works of De Quincey, a Life of Saint Patrick, the prose works of Milton and Tacitus (“until I could stand them no longer”), Samuel Dill’s Roman Society from Nero to Marcus Aurelius, the seafaring yarns of Jacobs, the poetry of Scott, Poe, and Longfellow, a German novel called Jörn Uhl, “a most satisfactorily lurid Man-eating Lion story,” and Foulke’s Life of Oliver P. Morton, not to mention at least five hundred other volumes, on subjects ranging from tropical flora to Italian naval history.

ADDED: I wanted to show you this wonderful Thomas Nast cartoon from 1874, which I found looking up who was Oliver P. Morton:

 

Wikipedia caption: “Thomas Nast asks Morton and three other huffy-looking inflationist senators, Simon Cameron, John A. Logan, and Matthew Carpenter, to pardon him for his caricatures, Harper’s Weekly, June 6, 1874.”
I love the meta quality of this cartoon. Nast apologizes to the caricatures. What a wonderfully insincere apology, repeating the very offense his own caricature seems to view as needing an apology!