A serious biographer has a love-hate relationship with the prior biography of his subject. At least, that is my relation with the biography of Stanton by Benjamin Thomas and Harold Hyman in 1962.
On the one hand I love the book because it presents a full and fair view of Stanton: the best life of him to date. On the other I hate the book because it is so laced with errors and so deficient in evidence. I am dealing right now with a good example. On page 284, they state:
“A brief lull in the pressure of events during the last days of August  gave Stanton a chance for a much needed break in his grinding routine. After combining an inspection tour of West Point with a brief stop at a New Jersey seaside resort, he joined Ellen and the children at a mountain retreat near Bedford, Pennsylvania, in expectation that Lincoln would meet them there as planned, but the President could not leave Washington. . . . During this pleasant, brief interlude, Stanton kept in touch with Lincoln and the Department by telegraph and through Eckert enjoyed continuous access to developments.”
One would expect, from this, to find evidence that Stanton was away in late August. I find none: and indeed it is clear that he was in Washington for the first few days of September: he was present at the Cabinet meeting on Friday September 4. See Chase Papers 1:436. It would then seem that he went away for a weekend, not to New Jersey or New York but to Bedford, Pennsylvania, for there is a message from Lincoln to Stanton there on Sunday September 6. See Lincoln Works 6:436. But Stanton was apparently back at his desk in Washington on either Tuesday September 8 or Wednesday September 9. There is a newspaper report (Wisconsin Daily Patriot) that suggests the 8th but the vast output of letters for the 9th suggests that as a more likely day.
So this was not a leisurely late summer tour of several different spots; it was a long weekend in Bedford. The only real evidence Thomas & Hyman cite is the Lincoln letter; they cite no newspapers about Stanton’s whereabouts; no daily reports from Eckert to the absent Stanton. They confuse, I believe, August 1863 with August 1865, when Stanton did indeed visit Highlands, New Jersey, and West Point, New York. And they mislead the poor researcher trying to follow in their footsteps.