Wilfrid Gordon McDonald Partridge (paperback)

Wilfred is a small boy who lives next door to an old people's home. He likes all the people who live there, but his favourite person of all is Miss Nancy Alison Delacourt Cooper, because she has four names just as he does. So when Wilfrid discovers that Miss Nancy has lost her memory, it is only natural that he should set off to help her find it.