The two sections that I felt were most beneficial for me to read at this point in my career were the "Picture it, Draw It" and "Building Number Sense" sections. The "Picture it, Draw it" section discussed the importance of asking students to represent their thoughts, and ask them "why?". Leinwald also mentioned that we should use multiple representations when teaching a concept, to cater to all of our student's background knowledge. The section on number sense stressed the importance of helping kids become comfortable with numbers and estimations, mental math, place value,and building number sense with each number they encounter. I believe a huge step in the right direction for mathematics educators is to help our students feel comfortable with numbers. When our students feel comfortable with numbers, they won't be afraid to struggle a little and learn on their own.
I would recommend this book to any future math teacher because it was enlightening and I will be a better teacher because of it.