Lytton Strachey’s Eminent Victorians is both a new and modern form of biography, rebelling against the standards of his period, and a return to the moral emphasis and form of Plutarch’s Lives of the Noble Greeks and Romans. Although the book is technically a work of non-fiction, like that of Plutarch, the point is not so much a recitation of historical facts as moral analysis of the characters of important people. Unlike the relatively genial Plutarch, Strachey sees himself at odds with the important Victorians and is intent on showing that they have feet of clay; this negativity somewhat distorts not his factual claims but his slant. For example, recent scholarly work on Manning suggests that Manning was, in fact, deeply concerned about poverty and the plight if the Irish, and Newman, by contrast, who Strachey uses as a positive foil to the negative Manning, somewhat less admirable and more self-centred than portrayed by Strachey.
As all have a balance of factual accuracy and distorted viewpoint, I am not sure one can settle on a “least accurate”; the Gordon portrait is probably the least distorted, and the Manning and Nightingale ones the most vitriolic.
Eminent Victorians is a collection of biographies of leading figures of the Victorian age, first published in 1918. It is difficult to categorize precisely because the point of the book is less to record the details of the lives of the author's (Lytton Strachey's) subjects than to use them as a way to advance his own caustic assessment of Victorian hypocrisy. In this regard his book resembles classical collections of biographies, such as Plutarch's Parallel Lives, or hagiography, such as a collection of saints' lives—books that celebrate the lives of great people as a way of articulating a common moral purpose. These resemblances are of course used for the purposes of irony, however, since the people he writes about are far from saints (including, even, Cardinal Manning and Florence Nightingale). So there is a sense that Eminent Victorians can be regarded as a polemic, or argument, rather than a biography; there is also a way it can be considered as satire. It is a surprisingly funny book.
Accuracy, then, is not exactly the first consideration of the book. If forced to pick the least accurate biography, critics often identify the section on Matthew Arnold as mostly fictitious.