Can there be any more difficult task in writing than to write well about abstract art? Almost by definition abstract art is beyond words; it deals with matters such as line, angle, shape, surface, edge, scale, colour, for example - that language is either clumsy about or even superfluous to.

Milan Mrkusich (born 1922), one of our greatest artists and a dedicated abstractionist for more than 60 years, presents the problem in fairly extreme form: What is there to say about such paintings? Given the difficulties, Alan Wright and Edward Hanfling, the co-authors, have done very well. They have produced a big, well-packed, well-researched, serious-minded study which I found so informative and interesting I read

it almost at a sitting. The authors are aided and abetted by high-quality colour reproductions both throughout the text and in a section of 95 full-page plates. It is a handsome, well-designed, well-produced hardback, good value for money. The plates are close to superb. While some Mkusich paintings are easy to photograph - those with bright flat colours, for instance - others are damnably difficult because of, for example,

the darkness and subtleties of some surfaces. On the whole, the publishers have succeeded magnificently.

Few Mrkusich paintings are famous in the way that certain images by, say, Angus and McCahon are, and most of the works included here will be unfamiliar to all but experts. But many are undoubted masterpieces and almost all reach a very high standard; the collective achievement is huge. People will have different favourites among Mrkusich's work. For me, the paintings on jute with loose gestural brush work from

the 60s are a big rediscovery; other favourites, among many, are the larger corner paintings of the 1970s: vast mysterious interiors with a triangular patch at each corner as if holding down the sky; impressive, too, are the late multi-part paintings, especially the majestic Journeys and Chinese Element series of the 1980s, which stack irregularly sized colour panels vertically or horizontally.

It enormously expands my perception of Mrkusich's achievement to see so many fine works, even whole series, that I hadn't known about before. (It is worth noting in passing that most of the works reproduced come from private collections, including his own; the holdings of Mrkusich works in public collections is lamentably small; the Auckland Art Gallery with seven works, the Hocken Library, University of Otago with six, and Te Papa with five are the best represented.)

As for the text and the problem of what to say about Mrkusich's art, the co-authors have found a rich and interesting story to tell, phase by phase, throughout his long and outstanding career. Their approach is fortunately not exclusively formal and analytical, but is also contextual, which leaves room for a more expansive and engaging discussion. For instance, they write about Mrkusich's significant involvement with the Auckland design and architectural communities in the 1950s; and about his relationship to the gallerist and critic Peter Vuletich, once his most impassioned advocate, in the 1970s.

The book also fully documents Mrkusich's transactions with international art. From the start he was constantly searching magazines and books for what was happening in London and Paris, and later New York. But he was a stay-at-home internationalist, a rare paradox. Although he seldom travelled - once to Australia and once to the United States in his 60s was all he clocked up - he was profoundly cosmopolitan and internationalist in outlook.

Thoroughly informed of every new development in world art, he entered, through paint, into a continuous dialogue with every strand of 20th-century abstraction: from the heroic European fathers - Mondrian, Kandinsky, Malevich, Rodchenko - through the British interpreters (Ben Nicholson, Barbara Hepworth, John Tunnard), and on inevitably to the post-war Americans, as the successive generations rolled through: the abstract expressionists (Pollock, Rothko, Barnett Newman), the pour-and-stain colourists (Morris Louis, Kenneth Noland, Helen Frankenthaler), the anti-metaphysical minimalists (Frank Stella, Elsworth Kelly, Jules Olitski), and many others.

Reading this book is a fast education in the history of 20th-century abstraction and Mrkusich, at the other end of the world from where it was happening, was there at every turn, never slavishly following but alertly interested in whatever was new.

The text also tracks in minute detail Mrkusich's technical changes and experiments - with materials, with supports, with new shapes and colours, through decades of dedicated practice, and also, importantly, documents his reading in Jung, Kandinsky and other theorists of symbolism and alchemy, essential to an understanding of Mrkusich's wider aims as an artist.

There is, among so much to praise, one surprising factual error. Speaking of the 10 Big Paintings show at Auckland Art Gallery in 1971 - a show in which many top painters such as Colin McCahon, Don Peebles, Don Driver, Robert Ellis and co participated - the authors claim (p78) that McCahon as an employee of the Auckland Art Gallery in effect pulled rank on Mrkusich and refused to permit him to paint his big work on site, as McCahon had done.

In fact McCahon had left the Auckland Art Gallery seven years earlier and had been teaching at Elam since 1964. It was in his studio at Elam that he painted his big work (Gate III), not at the gallery.

This unfortunate error - it quite falsely puts McCahon in a poor light - carries the whiff of old art world envies and rivalries, which the authors should have been sceptical about rather than taken as gospel. It leaves me with the uncomfortable sense of there being an element of propaganda as well as worthy advocacy in their approach to Mrkusich, a bias that Mrkusich's art, as triumphantly presented here, clearly has no need of.

* Peter Simpson is an Auckland reviewer and director of the Holloway Press.