THE last excursion H C Robbins Landon made to Venice was in Five Centuries of Music in Venice, a profusely illustrated guidebook that paid a brief visit to the Vivaldian sights and sounds. Here he returns for a longer pilgrimage, and takes the reader through the life of the Red Priest in a way that is designed to entice those already caught by the pyrotechnics of the Four Seasons to explore further the work of this still underestimated master of the Venetian Baroque.

Placing Vivaldi in his Venetian setting (duly supported by well-chosen illustrations, not all by Canaletto) is an important service, especially in an age that tends to remove music from its social, political and geographical context. The Vivaldi revival has concentrated on the instrumental music above all; it has glanced at the church music and almost completely neglected the operas. Robbins Landon argues that these (by far the larger part of Vivaldi's huge output) are largely unrevivable, at least in the present climate of musical taste. Stage conventions and antiquated librettos militate against them in a way which has not proved true of Monteverdi, Handel or even Haydn, and for the time being they seem fated to join the bulk of pre-Mozartian opera in the lumber-room of the library.

This does not deter Robbins Landon. He conducts a fascinating tour of Vivaldi's operatic career from its early Venetian beginnings in 1713 (just after Handel had made such a stir by his arrival, incognito, in the city), via his successes in Rome and Mantua and his troubles in Ferrara, to his disappointment and death in Vienna. His erstwhile patron, Charles VI, succumbed to a dish of poisonous mushrooms, leaving Vivaldi to die a pauper's death and suffer a Mozartian burial, with the young Joseph Haydn singing in his funeral choir.

Most of Vivaldi's operatic career was conducted on leave of absence (legitimate or otherwise) from his chief post, as music-master to the celebrated orphanage of the Pieta, where the female inmates provided one of the most famous musical ensembles in Europe from behind the grilles of the convent chapel.

Accompanying Vivaldi on his journeys was the celebrated singer Anna Giraud, or Giro, who spent most of her career with the composer as friend, nurse and companion. Vivaldi's strettezza del petto (probably chronic asthma) demanded constant attention, though whether Anna Giro provided more than mere nursing was a subject of scandalous discussion at the time, and Robbins Landon prints the full correspondence, with Vivaldi's impassioned defences of his and the lady's virtue, in one of the most entertaining sections of the book.

It is in printing Vivaldi's surviving letters in full, and much other correspondence in part, that Robbins Landon does the reader the greatest service. Letters, whether fawning or patronising, flattering or pleading, ranting or frankly begging for money, give all that can be had of the authentic voice: Goldoni's two conflicting versions of his meeting with Vivaldi show how unreliable reported speech can be, and how prone to caricature. Not that the caricatures of Vivaldi are to be scorned: one cartoon by Ghezzi gives the most convincing physical likeness, and other satirical pen-portraits do a a great deal to bring the composer to life.

But the greatest force in resurrecting Vivaldi has been the revival of interest in the instrumental music, especially the violin concertos. The Nigel Kennedy phenomenon (taken purely as a piece of pop culture) was what prompted the writing of this book, and it is to this astonishing change in Vivaldi's popular image that Robbins Landon constantly returns, not only trying to explain the effects of the music in terms a layman can follow, but looking at the rest of the work, especially the sacred music. Go to Venice in search of Vivaldi, by all means, but go first to the church or concert-hall, record shop or library, and encounter the music at first hand. This book, alongside Talbot's brilliant study, is a first-rate guide.