Peter Ackroyd’s “Chaucer” (Doubleday, 188 pages, $19.95) is the first title in a fearsomely ambitious new series of short biographies. Even Dr. Johnson limited his purview to the “Lives of the English Poets,” but in “Ackroyd’s Brief Lives,” the well-known biographer of Dickens, Blake, and Eliot intends to cover “the most important men and women in the history of the world.” That his first subject is, in fact, an English poet – and a Londoner, an inhabitant of the city Ackroyd has written about often and well – ought to make this book a strong start for the venture. In the event, however, Mr. Ackroyd’s “Chaucer” is a disappointment, a dutiful survey rather than a vivid evocation of the man or his age.

Geoffrey Chaucer is a challenging subject for any biographer. In his own poetry, he never takes center stage: Like the monks who drew themselves in the margins of illuminated manuscripts, he prefers to remain off to one side, a spectator of his own eloquence. In “The Canterbury Tales,” the poet deliberately makes himself the least vivid of the company of pilgrims, a distracted and comical figure, at least in the eyes of the merry Host: “‘What man artow?’ quod he; / ‘Thou lookest as thou woldest fynde an hare, / For evere upon the ground I se thee stare.’ “

These lines are fairly representative of Chaucer’s middle English; it may be blurry at first, but a little practice in looking makes it snap into focus. Only a few obsolete words need to be glossed for the passage to make perfect sense: “‘What man are you?’ he said; / ‘You look as if you would find a hare, / For I always see you staring at the ground.” Chaucer’s self-mockery becomes still more pointed: The tale he proceeds to contribute to the pilgrims’ story-telling contest is so boring and old-fashioned that the Host cuts him off, crying “Myne eres aken of thy drasty [filthy] speche.”

Chaucer is the creator not just of the Host and the other pilgrims – the obscene Miller, the demonic Pardoner, the defiantly vital Wife of Bath – but of the characters nested, Russian-doll style, within those characters’ tales: faithful Constance, proud Chaunticleer, seductive Alisoun whose body is “as any wezele … gent and smal.” But rather than claim his due as the God of this teeming Creation, Chaucer generously allows his own characters to upstage him.

For the biographer of Chaucer, this reticence is only the first of many obstacles to overcome. Chaucer delights in exaggerating his bookishness and unworldliness – “I knowe nat Love in dede,” he claims in “The Parliament of Fowls,” only “in bokes” – and he tells us nothing about his personal life. While he is the founder of modern English literature – the first writer in the language whose works can still be read for pleasure, as opposed to antiquarian curiosity – he makes no claim to originality in the modern sense. Like Shakespeare 200 years later, he did not invent his plots, but took them over wholesale from French romances, Italian novellas, and Greek legends. As he wrote in “The Parliament of Fowls,” in a passage aptly quoted by Mr. Ackroyd:

For out of olde feldes, as men seyth,
Cometh al this newe corn from yer to yere,
And out of olde bokes, in good feyth,
Cometh al this newe science that men lere.

If Chaucer tells us little enough about himself, other sources are almost as unforthcoming. His life is well attested in contemporary records, from his birth around 1341 to his death in 1400, but all these records refer to Chaucer in his official, nonliterary capacities: as diplomat, bureaucrat, property holder, and occasional criminal defendant. (A woman named Cecily Champain apparently accused him of rape, then dropped the charge – frustratingly, no details of the case survive.)

His poetry must have been popular with his courtly audience, to judge from the number of surviving manuscripts – there are some 80 versions of “The Canterbury Tales,” which he apparently never gave any final form or sequence – but we can only guess at the exact circumstances of his reception. His private life, too, is veiled. He seems to have mostly lived apart from his wife Philippa, who also had an appointment in the royal court. Still less is known about his parents and his children. Only his official appointments – as emissary to Genoa, customs collector, clerk of the king’s works – are thoroughly documented, and even here we know little about what Chaucer was doing on any particular day.

Mr. Ackroyd’s short book competently surveys the evidence of Chaucer’s life and makes a hurried tour of his works, from the translation of the French “Romance of the Rose,” through shorter poems like “The Book of the Duchess” and “The House of Fame,” to the masterpieces, “Troilus and Criseyde” and “The Canterbury Tales.” But he has nothing new or striking to say about the life, the work, or the times of Geoffrey Chaucer, and his prose is seldom better than serviceable.

Only when he evokes the streetscape of medieval London does he seem energized: “At dawn in Cheapside the whole city would awake around him. The bell rang at the church of St. Thomas of Acon, at the corner of Ironmonger Lane, on the hour before sunrise; then the wickets beside the great gates of the city were opened, and through the darkness trailed in the petty traders, the chapmen, the hucksters with baskets of gooseberries or apples.” At such moments, Mr. Ackroyd is back on his favorite ground. The rest of the time, it is hard to guess why he chose to begin his ambitious venture with a subject to which he can bring so little passion.