Possible Level 1 toddler, book recomendations?

My 2.5 year old is undiagnosed showing some tendencie of ASD. I'm obviously unqualified to diagnose but level 1 ASD seems most likely to me.

I was wondering if there are any book recommendations, both for better understanding ASD, as well as helpful parents for understanding, redirecting, teaching to help the little guy.

Just trying to get more educated. Thank you.