Arthur Mee's children's encyclopaedia (New Greens AL3)

This ten volume encyclopaedia is sadly not dated, but perhaps the portrait of Queen Elizabeth II gives a clue.
It is not arranged alphabetically as a traditional encyclopaedia would be, but rather consists of a large number of articles which can be followed systematically or dipped into. There are many pictures, some in colour, as the portrait of the queen illustrates.
Some of the information will inevitably be dated, but much of the content remains timeless, such as history, poetry and classic stories.
Best wishes, Ian.