"Matthew's parents are worried. At eleven, he's much too old to have an imaginary friend, yet they find him talking to and arguing with a presence that even he admits is not physically there. This presence - Chocky - causes Matthew to ask difficult questions and say startling things: he speaks of complex mathematics and mocks human progress. Then, when Matthew does something incredible, it seems there is more than the imaginary about Chocky. Which is when others become interested and ask questions of their own: who is Chocky? And what could it want with an eleven-year-old boy?"
Wyndham, at times, is slightly dated (in this case, he's a bit idealistic about radiation and as usual his female characters leave much to be desired) but his storytelling is tight and top notch. His novel/las have tight and subtle plots and I always enjoy both the overt plot and the subtle understory he crafts. You always know, just know, how it's going to end but Wyndham takes you on a good journey there. This is a strong case of how an intelligent alien life could make first contact. I bought the premise. I liked it even.
This is a great example of good science fiction. There's no in-your-face techno jumble and there's no need to create a whole new world because the science fiction is integrated into a contemporary (1960s) typical suburban atmosphere. The pace is controlled not frenetic which allows for a slow contemplation of the implications and possibilities. That allows for a quick suspension of belief. The point of view (from the father) allows for the reader to be taken from skepticism to believing. Subtle manipulation.