All the D'Aulaires books are wonderful - but if you are looking for a beautiful present- get Greek Myths and Norse Myths. They are masterpieces.
P.s. This is an American published book - which I bought from the American Amazon site (no more expensive than here, but it wasn't available on any European sites) and it is about Leif's landing in the States. I did wonder whether I should be buying kids books on Irish history, seeing as that is where we live, but then noticed that in my sons (Irish) First Class workbook, there is a section on Leif - which gave me the perfect excuse to buy.
P.p.s. Cartoon Salon, who were recently nominated for an Oscar for their animated film Song of the Sea, have illustrated a funny and information book about Irish history The Story of Ireland. Its great!