identify a book i read as a kid (about 25 years ago!)

[mandimoo]

all i can recall is that the young main character of the book was able to, or learnt to astral travel. they were warned of the impending journey by an alteration of their perception of the world around them. one particular occurence of this was some papers, or maybe leaves being gusted around in a wind. I have an inkling that there may have been more than one book.