Only in Rachel Cade (still Mercer's best book in this reader's opinion) did Charles Mercer share his love affair with Africa. That story was set in the region of the Mountains of the Moon; Pilgrim Strangers I given an immediacy by its Congo background. And again the whites in the district are medical missionaries. The substance here is exciting and vital --picturing the challenge posed when the whites must leave, even if they are Americans who have served a lifetime for the Africans. But the manner of the telling robs it of some of its authenticity, as it purports to be a 14-year old narrating the story. Not only is it unconvincing that Melissa could sustain the record, but it suggests a much more searching penetration of the psychological aspects than would be possible even for an observant youngster to sense and convey. Granted this weakness, one must grant also the appreciation of a growing sense of Africa, as it might well have been experienced by the three kids; their hero worship of their father, a flier dedicated to helping those who needed it; their reluctance in yielding their preconceptions of what missionaries would be like- and accepting them for what they were; even their slow growing conviction that there was a God- and that faith had its merits. The romance, forwarded by the children, between their father and the teacher at the mission station, provides a predictable but warmly human factor. But the importance of the book lies in the picture it gives of the grave problem that is the Congo today.