Maiden aunt of art shows the family treasures

This is not a convenient guidebook to the National Gallery collections, its size and weight defying even the strongest tourist to drag it into Trafalgar Square. What it is, is a delight to read and examine, a model of easily assimilated scholarship and presentation which replaces the rather dull and unwieldy 1973 catalogue. One could call it a paper romp through one of the finest museums in the world; with just three paintings to a page (mostly reproduced in adequate colour) it successfully sets out to present the reader with every work in the gallery's collections. Although most appear on the page little larger than a small Post-it, they succeed in providing the images one needs to augment the substantial yet clear catalogue entries and notes which are concise but often fascinating in unexpected details.

This then is a source book to the collections, and as the museum director Neil MacGregor points out in his introduction and gallery history, this is a remarkable collection of paintings: "perhaps the most evenly balanced, across all European schools of any in existence". Indeed the collection stretches from the 13th to the 20th centuries and yet remains "uniquely accessible to the people that own it: under normal circumstances, every one of its 2,000 or so paintings is on public view, and can be seen without charge." The catalogue then becomes an extension of the director's primary aim, "to allow readers to take hold of the collection as a totality, to gain an overview of its defining characteristics, its strengths and its weaknesses, to familiarise themselves with it, and to decide what particular pictures they want to come and look at." Then follows a fascinating concise history of the gallery which remarkably is alone among the great European collections for being formed not by making a royal collection public but by a parliamentary decision in 1834 to provide great pictures for everyone's enjoyment. First housed in the director's Pall Mall residence, then opened to the public, this was truly a remarkable public-spirited venture. The gallery interior was also extraordinary, its mock rococo plasterwork walls and high mansard ceiling hung with pictures.

Over the years with vigilant public attention the fate of the British collections was sealed. The Tate Gallery (opened in 1897) was meant to house a national collection of British art and European painting after 1900. Yet there are overlaps at the National Gallery. Confusing as this may seem (and it still rankles with some) MacGregor tactfully quells further controversy by admitting that the dividing line between the Tate and National Gallery collections is a fluid one with pictures moving in both directions .

The present gallery building in Trafalgar Square is more intimate than grand, more accessible than intimidating. Unlike galleries in Washington, the Metropolitan in New York or the Louvre in Paris with their lofty and grandiose entrances the London National Gallery is like a maiden aunt carefully poised over the square, staring down upon Lord Nelson and the lions. There it sits like a great secret waiting to be revealed, a treasure house that has grown from just 38 paintings (bought from a private banker for Pounds 60,000 in 1824) to the more than 2,000-work collection we have today.

This then is a fitting catalogue for such a important and accessible institution. The entries are augmented with almost 40 pages of indices by subject, artist and bibliography of current research. Pictures are described by technique to alleviate the mystique of period connoisseurship. Theories and doubts about attributions are openly discussed as are a picture's iconography and authorship. In this age of laser knowledge and chemical analysis there is a real need for accurate attributions. One only wonders at the half columns of white space left below each catalogue entry, the space seemingly ready for further research and inserts about a painting's importance.

To find art so accessible these days, free from security barriers, perspex boxes and video cameras is a real joy. Long may the National Gallery thrive as the friend and comfort to art lovers who enter Trafalgar Square.

Rodney Engen is an art historian and author of numerous books including his most recent, Pre-Raphaelite Prints.