Cezanne is identified repeatedly as the father of modern art but with this most comprehensive survey of his work for 60 years offering a rare occasion for reconsideration, the Tate Gallery’s Notes for Teachers and Group leaders pertinently asks if we are absolutely sure we know why.

Gauguin, Matisse and Moore are among the many artists who have bought and been influenced by his work and nowadays even secondary school pupils know how important he was for the Cubists and their more abstract followers. Both during his lifetime and over the nine decades since his death, Cezanne has been many things to many people and this diversity of understanding, encompassing formalist, phenomenological and psychoanalytical interpretations, is acknowledged in the programme of talks, study sessions, conversations and international conference that accompany the exhibition.

Once inside the exhibition, however, it is the sheer diversity of the work itself that will surprise. A few years ago, the Royal Academy acquainted us with the wildly romantic, orgiastic and downright brutal aspects of Cezanne’s early paintings. Here we discovered deep levels of fantasy and associated experience as well as the unexpected moments of tenderness revealed in the shocking presentation of the grossly misshapen body of fellow-painter, Achille Emp-eraire a large picture given prominence at the Tate.

Most visitors will be familiar with Cezanne’s brief, if important, encounter with Impressionism and will know the famous still lifes and landscapes that followed. But how many know Cezanne the portraitist, the painter of the nude and complex figure compositions, let alone the innovative draughtsman and exquisite watercolourist? All take their place here.

Throughout this year, the Tate’s education department is focusing particular attention on sketchbook work, and exploratory drawing underpins not only the workshops for key stage 3 and 4 that arise out of Cezanne’s sense of place, but the day-long conferences on March 21 and 28 for students and teachers at A-level and GNVQ which explore Cezanne’s landscapes, still lifes and figure compositions.

Paper-based drawings, watercolours and mixed-media pieces in all these categories, from a capably-executed, academic nude and heavily-worked “Feast” of the 1860s to the near-transparency of “Still Life with Green Melon” and “Mill on A River” done in the last years of his life, thread their way right through this exhibition. On two occasions, the predominantly chronological account of the artist’s development as painter in oils pauses to take stock of his achievements in other media.

After repeated claims that Cezanne could not draw, even traditionalists must concede distinction in the head of a “Peasant Girl Wearing a Fichu”. Younger students unaffected by academic prejudice will admire and very likely envy the distillation of form in “The Forest” a watercoloured drawing that epitomises Cezanne’s luminously economical final style even in oil paint.

The just as often-repeated charge that Cezanne was no portrait painter is also reversed. Three self-portraits from the 1870s alone suggest his extraordinary range of response and lend support to a show devoted entirely to images of himself. The inclusion here of such very different representations as the sombrely reflective and heavily impastoed “Portrait of A Man” (almost certainly Cezanne’s old school-friend, Antony Valabreque), the near-possessed head of Cezanne’s great supporter, Victor Choquet, and the resigned “Madame Cezanne in a Yellow Chair” more than justify the space given to likenesses of family, friends and equally riveting, if anonymous, employees.

Undoubtedly the category in which Cezanne’s absorption of his classical past and fertile influences on his future painting are most evident is that of figure composition. More so than in the still lifes or landscapes, exceptional though they are, the almost uninterrupted series of single and elaborate groups of figures out of doors confirm his pivotal position in a tradition that stretches from Veronese, Rubens and Delacroix to Matisse, Picasso and even de Kooning. Cezanne modestly claimed he was the primitive of a new art. This exhibition unambiguously reveals him to be its first master.

Teachers planning group visits can prepare themselves and their students with free preview evening and notes. And whether they indulge in the justified cost of the massively comprehensive catalogue Pounds 35 (pb) Pounds 55 (hb) or not, they will find Paul Smith’s Interpreting Cezanne (Pounds 9.95 by mail only), specially commissioned by the education department, an invaluable help in unravelling the often conflicting commentaries on the artist’s intentions, techniques, realisation and meaning. For details, telephone 0171 887 875967