Profile Of A Collection, IMMA, Dublin, until June 23rd:  When the Irish Museum of Modern Art was being established a little more than a decade ago, one of the problems facing it was the lack of a collection of modern Irish - and, for that matter, international - art. There is a considerable difference between assembling a collection retrospectively, in one fell swoop, and incrementally, over a period.

Operating in retrospect, you are exposed to the vagaries of the market, trying to acquire works that have appreciated immeasurably in value, monetary and otherwise. Whereas if you buy art continually, over time, you can amass a fantastic collection at a fraction of the cost.

While IMMA's first director, Declan McGonagle, made a virtue of necessity by shifting the focus of the institution away from the concept of a fixed, canonical collection, there is all the same, as he recognised, a certain onus on a museum of modern Irish art to house and display a collection of modern Irish art.

Which is where private art collections, and perhaps other institutions, come into the picture - the latter, it must be said, more in theory than in practice so far, although IMMA has benefited greatly from short- and long-term loans from a variety of institutions.

Private collectors often turn out to be benefactors. As Harry Crosbie, referring to his own collection of art and antiquities, pointed out to Carrie Crowley in a radio interview at the weekend, you don't so much own that kind of thing as have it on loan for a while; it will outlive you. Which may be part of the point of collecting.

For a small country, Ireland boasts a good number of contemporary art collectors who have bought consistently, intelligently and often adventurously over the years, none more so than Gordon Lambert.

To his immense credit, Lambert was keen to see his collection find a home in IMMA even before the museum existed. Like many others, he saw that the lack of a museum of modern art was a serious shortcoming in the cultural life of the country.

He has recorded his dismay on seeing the dispersal of a major private collection after the death of Sir Basil Goulding, something that strengthened Lambert's resolve that his own collection should go to the State in one way or another.

Fortunately, the advent of IMMA provided the best possible destination for one of the most remarkable private collections in Ireland. He not only donated his work to the museum but also established a trust that continues to direct works into the collection - additions since 1992 include pieces by Mark Francis, Sean Scully and Howard Hodgkin.

Now, Profile Of A Collection, which consists of 55 works selected from the Gordon Lambert Trust Collection, not only gives an idea of the range of work it includes but also provides a chronicle of Lambert's collecting. From the first, this collection has been a cornerstone of IMMA's holdings and has, arguably, encouraged the generosity of other collectors in the provision of loans and donations.

At first glance, Lambert is an unlikely art collector. An accountant before he retired, he was for many years managing director of Jacobs Biscuits Ireland.He came from a family renowned for its sporting achievements - his father, a vet and a keen cricketer, was dubbed the W.G. Grace of Ireland. Rugby, badminton, golf and tennis were also family pursuits.

Art might never have impinged on Lambert's world, but he happened to know some people who were then "part-time painters", including Cecil King and Barbara Warren. The first work he bought, in 1954, was by Warren. Once he became interested, however, and once he started looking around with a view to acquiring pieces, he seems to have discovered a distinctly independent critical sensibility in himself.

Soon he was eschewing received opinion and following his instincts, which led him eventually in the irreverent direction of innovative artists such as Michael Farrell and a youngster called Bobby Ballagh. Besides acquiring significant examples - often many examples - of the work of important Irish and Irish-based artists, including Patrick Collins, Cecil King, Barrie Cooke and Patrick Scott, he had no hesitation in looking further afield.

While, he emphasises, he did not have unlimited funds at his disposal, he was patient and selective and managed to buy prints by Picasso and Braque. More surprising, perhaps, was the passion he developed for pop and kinetic art following a ground-breaking exhibition at the Hendriks Gallery in Dublin in 1966.

It could be that the intricate patterning appealed to the number-cruncher in him. Hence the presence of artists such as Victor Vasarely, Bridget Riley and Carlos Cruz Diez in his collection, and a strong international representation.

ART, artists and collecting became progressively more important to Lambert. When Eithne Waldron, of the Hugh Lane Municipal Gallery of Modern Art, invited him to exhibit his collection there in 1972, it seemed to him, he wrote, that "fate was indicating that collecting modern art was not only a pleasurable hobby but a purpose in life".

Exceptionally keen to exhibit his collection, Lambert became known as a collector; became, in fact, an evangelist for the cause of modern art, something that led to his being appointed a senator in 1977.

Through his myriad involvements in various organisations, events and projects - too numerous and diverse to mention here, though his chairmanship of the Contemporary Irish Art Society is worth highlighting - and apart altogether from his connections with and donations to IMMA, he has contributed greatly to the enrichment of Irish cultural life.

Still, his enduring monument is likely to be his exceptional gift to IMMA, which is, in the words of Catherine Marshall, the museum's head of the collection, "that rare thing - a truly cosmopolitan collection with a perfect balance of local and international artworks".