HOW CURIOUS that two biographies about great Victorians should have appeared almost simultaneously, with titles which stress their subjects' disturbed states of mind! Tennyson: The Unquiet Heart and An Uneasy Victorian: Thackeray the Man provoke in the reader the question: Were men really so much more at peace with themselves at other times?

One thing is patent: it was not their Victorianism that made Tennyson or Thackeray suffer (both grew up under the Regency, George IVand William IV) but their circumstances.

If they avoided in themselves the madness (only just in Tennyson's case) that so often accompanies genius, madness is the dominant theme in Thackeray's sad story. The madness of his wife, after only five years marriage, left a tender-hearted Thackeray bereft of the natural outlet for his affections and, in the full force of his manhood, in "Want of a woaman," as he forcibly spelt-out for his mother to understand, when she lectured him lest he take a mistress.

His fastidious recoil from doing just that, and his miserable love for Jane Brookfield, the siren-wife of his friend William Henry Brookfield, were the root-cause of his sexual "unease."

Ann Monsarrat deals most effectively with the Brookfield entanglement, which, except that it gave us Henry Esmond , was the most destructive experience of Thackeray's life. Her book is immensely alive, written with verve and a never-failing sense of the abundance of the man and the oeuvre, and of the fullness of life crowding the background to his career. The book has dash, a quality Thackeray himself so much admired.

It is not strictly academic (and I will get over my grumbles at the outset), makes deplorable use of slang, like "way out," and designates Charlotte Bronte's letters to Thackeray as "screeds." However, the fund of facts it spills out like an overfull cornucopia more than compensates for the lack of selectivity. Its chief defect, and this is serious in biography, is the scarcity of dates and the want of precise references to source materials.

The book's positive qualities, however, are heartwarming. It is written with love and projects, even more than Trollope and Saintsbury did, the richness of Thackeray's endowments. Totally new are the pen and pencil sketches, lately discovered in the Charterhouse repository of Thackeray's manuscripts. In no other biography have the follies that went with his expansive temperament been so frankly, yet so charitably, dealt with. Nor has it been so well demonstrated that Thackeray himself, not merely his detractors, was his own harshest self-accuser.

Honesty was the mainspring of his character -- honesty coupled with that fastidiousness which he himself recognized as the hallmark of a gentleman. A gentleman could lapse so far, but no further; he could join company with Bohemians but never with cads.

It was his honesty that made him reject the hypocrisies of the nouveau-riche society of the 1850s; and how perfectly suited to such a man was the foundation of Punch at the crucial hour! How he scourged that "Brummagem" society! Above all other shams how he hated the marriage-market to which such noble girls as his character Ethel Newcome were immolated, for at heart he remained a sentimentalist all his life. "Although my marriage was a wreck," as he told a friend, "I would do it again, for behold Love is the crown and completion of all earthly good."

Monsarrat's book will make Thackeray more fairly known to a whole new generation of readers.

Tennyson: The Unquiet Heart is biography at the top flight of creative writing. One does not know what to admire most: the scholarship, the imagination, the judgement, all so finely blended as to leave the reader conscious only of their presence, but never intruding on the narrative flow, any more than do the bars in a musical score.

From the outset Robert Bernard Martin's judgment of character is apparent, not only in the portrayal of his protagonist but of the whole group of those Erinys-like figures of Tennyson's terrifying relations -- decisive, if ever a man's relations were, of his destiny. In the curse of his heritage -- a grandfather, father, uncle, brothers, afflicted with epilepsy and addicted to drink and drugs -- lay the source of that "unquiet heart" that Tennyson's biographer sees as his distinguishing feature.

With home like hell, who wonders that poetry was his sole and obsessive joy? With fine perception Martin has traced some of the actual scenes that inspired the imagery of the early nature poems: the varied landscape round Somersby, the trees and waterways, the Pyrenean waterfalls, that recur like leitmotifs over the years; and more hauntingly still, the symbol of the sea as the pathway to eternity, first seen at Maplethorpe.

Happiness of the human sort first reached him at Cambridge, where an elite generation of students that included Thackeray, Monckton-Milnes, James Spedding, John Sterling and Arthur Hallam were his friends. Their admiration, affection, faith in his powers, meant more than such friendships usually do to his lonely heart; he had known nothing like it. Their admiration, especially Hallam's, was balm to his wounded pride.

Of the famous Tennyson/Hallam friendship, Martin's analysis appears the most understanding that has yet been advanced, bedevilled as it has ever been by the very imagery of In Memoriam . "Love," as he finely points out, need not be confined, in post-Freudian terms, to either heterosexual or homosexual divisions: it can defy either category; it can co-exist within the wider ranges of "sympathey, companionship, likeness of interests . . . habitual proximity . . . . It was surely these feelings that were at the heart of Tennyson's friendship with Hallam."

Most importantly, the author shows the death of Hallam in its right perspective: deeply afflicting Tennyson and, without doubt, inspiring the "elegies" of In Memoriam , but not the whole poem's substance. Nor, even less, was Hallam's death the sole cause of the poet's melancholia during the following years and of his break with his fiancee Emily Sellwood.

It is very striking that for at least four years after Hallam died in 1833 Tennyson continued his sociable descents on his London friends and his tireless tramplings up and down the country in pursuit of natural beauty. Only after the disintegration of his family life and the move from the old home, the successive lunacy of his younger brothers (confined for life) and the rising hysteria of his sisters, did the conviction of his own doom from the family curse -- epilepsy -- overwhelm him and provoke that rooted melancholy that caused his withdrawal from his friends and the breaking-off of his engagement in 1838.

The "trances" into which composition threw him, those states of "lost identity" in which he was absorbed into his vision (very reminiscent of Emily Bronte) only confirmed his fears. His rootless life had only his poetry for anchor. When this was denied him by the venomous attacks of the critics -- J. W. Croker, Edward Bulwer-Lytton, John Wilson -- he lost all incentive in life. He became in fact, as in imagination, a tramp, a prey to the most cruel hypochondria.

He always exaggerated his poverty (another impediment to marriage) and believed himself destitute. He nearly became so when he invested his tiny capital in a bogus scheme proposed by Dr. Allen of Epping, the mental specialist in whose care he had placed himself.

Happily, ther were other doctors, notably Dr. James Gully of Malvern, who, while treating him with the fashionable hydrotherapy, managed to convice him he was not epileptic; that he could be a healthy man leading a normal life. From Gully's hands Tennyson emerged a new man, to resume his old friendships and claim his fiancee, abandoned for 10 years.

Marriage, financial security and above all fame, that so quickly followed the publication of In Memoriam , all in the one "Golden Year," 1850, transformed Tennyson's life. He was 41. He lived for exactly as long again.

What most strikes the reader of this enthralling book is how, despite the "grief and pain," it was the first half of Tennyson's life that produced the greatest poetry and the more interesting man. It was in the tumultuous years that he was, indeed, the Olympian poet, throwing up such masterpieces as "The Lotos Eaters," "Ulysses," "The Lady of Shalott," "Mariana," the nature poems, the elegies for Hallam, as the geological birth-throes threw up the mountains. The success story that followed makes rather sad reading; with the emasculated Arthurian knights (human psychology always eluded Tennyson) replacing the passionate lyrics of the early visions.

The change is typified even in the poet's appearance: from the glorious Apollo of the beginning (despite the dirty linen and unkempt hair) to the bearded patriarch of the apotheosis -- bearded to hide his damaged teeth.

Happily, there is "Crossing the Bar" to remind us that the Olympian flame was never quite extinct.