Chapter and Picture Books?

I swear, I was going through old books I used to read as a kid like those Animal Ark books and I ran across a picture book that had me as a main character lol. It was bound and everything but I'm pretty sure it was done by some friends of my parents years ago. I must have been one or two years old back then. Lol, somehow I saved the world from aliens?

I sat there, pulling book after book out of this box. All these Animal Ark stories and I remembered just about all of them. Is it a bad thing I'm planning on taking at least three back to college with me for "research purposes". :)

Seeing all these books that I absolutely LOVED to read made me realize how much I would like to try to write for the younger readers in terms of chapter books and maybe a picture book or two. I already have a character in mind from a MG, I was just wondering if anyone knew of any good sources for learning about chapter books. If you do, feel free to leave a comment or link :)