Susie Shellenberger has a pretty good idea about what's up with kids these days. The former full-time youth pastor and high teacher now fields more than 1,000 emails a month from teenage girls when she's not talking with them on her radio show or speaking to them from the stage at the Girls of Grace conferences.

After penning more than 30 books, including Dear Diary, Girls Want to Know, and Girl Talk with God, she's turned her sights on the Bible. Her study guide series, written especially for girls, debuted with 1 and 2 Thessalonians and now continues to 1 and 2 Timothy.

Highlighting the loving relationship between Paul, as mentor and Timothy as loyal disciple, she shows that Christianity is not just an emotional experience, but a conscious decision to engage in a trusting relationship with God. Using her own mentoring skills, she gently steers teenage girls towards a better understanding of their lives in Christ.