I have to declare an interest: for many years the Knight and I were the closest of friends until a sequence of his unpredictable and volcanic rages drove us apart. Robert O’Byrne explains how the Knight suffered for most of his life from the illness and strong medication of manic depression. It is a tribute to him that I never knew of this medical diagnosis until much later and that, despite it, he achieved so much in his life, drawing international acclaim to Irish pictures, architecture and furniture and producing so many learned books on their quality and beauty.

In fact there is a photograph in this book of the Knight and I dancing a jig to the melodious tin-whistle music of Paddy Maloney. But in the caption I am described as someone else, albeit a cousin. This has prejudiced my view of the factual accuracy of this book, which has an irritatingly bad index. The title and the front cover are very alluring, but this is not a biography. I hope that will come soon. It is principally a detailed account of the Knight’s lifelong and painstaking research, and of his beautifully designed books.

He wisely wrote most of his books with a partner, in particular the redoubtable and formidable (but charming) Professor Anne Crookshank (Ireland’s Painters and Watercolours of Ireland). The climax of his life’s work was his last book, Irish Furniture, with James Peill, an essential book for any library.

There is also much about his beloved Glin estate, into which he and his wife, Olda, poured every penny available, much of it into its conversion into a five-star hotel, which fared so badly in the recent recession that it had to close. This probably led to the special sale at Christies of much of his life’s work as a collector. It raised a million or two, which has left Glin in fine shape for the future.

I am glad to say that O’Byrne pays tribute to the ‘powerful influence’ on the Knight’s career of Mariga Guinness in the 1960s, whose immense knowledge, style, enthusiasm and wit inspired so many of the Knight’s and my generation, and which is seldom acknowledged by those who benefitted. The book’s sometimes leaden prose is much enlivened by the many quotes and contributions from Christopher Gibbs, who writes with a sparkling style to recreate the atmosphere of a glorious period of fun and laughter, which the Knight inspired in his best moments.

This book often refers to the Knight as a distinguished and honourable Irish patriot. Even if the Fitzgeralds date back to the 14th century, they were a slightly parvenu and anglicised family compared to the Gaelic clans of the O’Neills and the O’Donnnels, and maybe even the O’Byrnes. This is a short and inexpensive book, worthy of any Christmas stocking.