Hi J.,
The 2 books I am about to mention ARE controversial, in that you will find tons of good reviews about them but you will also find several critics. All I can say is that they have been VERY VERY helpful to me espcially as a first time mom. I would recommend them to anyone open to hearing their perspective on babies, kids & discipline.
The first is On Becoming Baby Wise by Gary Ezzo and Dr. Robert Bucknam. This is a series, and while the first focuses on Sleep issues and the purpose of "parent -centered" parenting vs. "Child-centered" parenting The second book which is smaller focuses on discipline. Both are good reads.
The second book is called Shepherding a Child's Heart by Tedd Tripp. His teaching is Excellent and I even got to hear in person at a recent parenting training. I gained a lot of Wisdom from both books and I hope you find them to be helpful.
One last resource, that is equally as controversial is both a book & website. I don't have the book but frequently utilize the website when I have questions. It is called Raising Godly Tomatoes by Elizabeth Krueger. I don't agree with everything she says BUT she has a lot of helpful tips in the areas of teaching obedience to small children.
I hope this is helpful. Happy Mother's Day!