You Can Adopt: An Adoptive Families Guide
by Isolde Motley
This was by far my favorite of the adoption books I've read so far. Super positive and super helpful.
Check out the #adoptionrocks hashtag and follow, follow, follow. It's so helpful at a time in your life when you're not sure what your family will look like to see beautiful, happy families formed through adoption. (some pictures will be pets. but I like pets too...)
For someone in your life who is feeling negative or hesitant about your plan to adopt:
Adoption Is a Family Affair!: What Relatives and Friends Must Know, Revised Edition
by Patricia Irwin Johnston
This was the first adoption book I picked up. It's framed for parents of prospective adoptive parents - so, my parents, for example - but it assumes they are not supportive of the choice to adopt. I found it to be a tough read because it's combating all the negative perceptions of adoption - which I was previously unaware of! I'd recommend it if anyone in your life is being negative about your adoption, but I don't really recommend it for prospective adoptive parents - at least, not until you've read other resources first.