I read Into the Dream three or four times when I was in 5th-7th grade. Loved it. But for the life of me, I could never remember the title, even then. The cover I remember was different, too--it had a Ferris wheel in the background, and there's a picture of it on GoodReads, but it's tiny. Anyway, maybe now that I've learned the title (again) and posted it here, I'll be able to remember it.
Premise of the story: Two friends discover they're having the same dream about a little boy in danger and, on the understanding that it's not just a dream, feel compelled to help him. And somehow, there's a psychic dog involved. I only remember bits and pieces, but I don't think I'd want to reread it as an adult because I'm pretty sure that as an adult reader, I'd be a little disappointed.
Nonetheless, I'm excited to have re-discovered the title and would recommend this book heartily to kids in grades 4-6. (I think I read it for reading class in 7th grade, but it was way below reading level then.)