Not easy to find these days - at least not at a reasonable price - The Modern Boy's Book of Racing Cars, published by Amalgamated Press in 1938 is a wonderful period piece. Mainly featuring writers and pictures from The Autocar, it was aimed at the younger market and was populist and tabloid in style but – even today – is no less interesting to anyone seeking a feel for the way motor sport was viewed at the time: it includes articles by Leslie Brooke – on his eponymous special – broadcaster Alan Hess, Sammy Davis, Bill Boddy and George Monkhouse.
A more technical volume - probably a bit beyond a child of eleven though - also published in 1938, is Power and Speed, edited by Frederick E Dean. It was “primarily intended for the more knowledgeable sections of the younger generation”. This covered all aspects of the use of the internal combustion engine – land, sea and air – and brought together writers from nine of the magazines published by Temple Press, including The Motor and Light Car. It also featured articles by John Cobb, Sir Malcolm Campbell, Prince Chula and racing driver/test pilot Chris Staniland, who contributed an autobiographical essay called 'Wheels and Wings'.
Don't discount the likes of The Eagle Book of Cars & Motor Sport - or even some of Sammy Davis's books, which are really quite accessible.