Harold Nicolson''s Diaries and Letters, spanning the years 1930 to 1962, were first published in three volumes, and it is in this format Faber Finds is reissuing them. The one-volume abridgement available in paperback from Phoenix is practical, and in itself a superb piece of compression, but such a great work, one of the major diaries of the twentieth-century, deserves also to be available in its full original incarnation.

This is the war volume. From the first page to the last Britain was at war. From 1940 to 1941 Harold Nicolson was Parliamentary Secretary to the Ministry of Information; subsequently he was a Governor of the B. B.C. Throughout he was in the perfect position to observe and describe, knowing the chief actors, Churchill, de Gaulle, Eden and many others. He experienced with acute anxiety and mounting excitement the fluctuating fortunes of the war, and came to share a mood of unreasoning faith and simple patriotism with the rest of the country. In July of 1940 he wrote, ''I have always loved England. But now I am in love with England. What a people! What a chance! . . . The chance that by out stubbornness we shall give victory to the world.''

''One stops to marvel at the achievement. Honesty, decency, modesty magnanimity are stamped on every page, as evident as the wit. These are not the normal virtues of successful diarists or would-be politicians, but Harold Nicolson possesses them all.'' Michael Foot, Evening Standard

''He remains completely unaware that he is tapping out a masterpiece. Brilliant though he is as historian and man of letters, the diary will keep him best remembered. As lively as Creevey or the de Goncourts, Sir Harold is a peer of those classics. Mr Nigel Nicolson has again done a superb job of editing and annotating.'' A. P. Ryan, The Times