Wyndham's last substantial work before his death is a great way to go out. The story tells of a boy's imaginary friend who turns out to be a telepathic alien child reaching out from across the vastness of space. Wyndham imbues it with fantastic insights into the nature of language and communication and the delicate nature of family relationships.

Essential SF, and like much of this author's work, should appeal to non-genre readers too.