Don’t remember the title but here’s what I recall:

This is a children’s book from the 1960s or even late 1950s with a narrow/slim size. I have attached a photo of a similar book that might even be from the same series.

It has a shiny light blue cover. The content is about signs of fairies in the forest/nature. It’s a series of photos with little text. It shows photos of dew, spider webs, etc. might have an illustration of a fairy on the front of the book.