An infant survives a shipwreck and ends up on an island where he lives alone for a few years. Not certain what age he is when some people (grandfather maybe) come searching for him, but not being accustomed to people, he hides from them. The book makes a point of mentioning that the boy’s hair is very blond to almost white. I remember this was a very tiny book size-wise; smaller than the average book at the time.  It was a library book from the young adult/children’s section and I read it in the late 60’s early 70’s.