|Other Retailer||Price Checked Time||Their Price in AUD||Our Price|
|Amazon UK||4 days ago||36.23||$16.65||You save $19.58|
|Amazon US||yesterday||17.3||$16.65||You save $0.65|
|Book Depository US||today||16.7||$16.65||You save $0.05|
About the Authors Frans Plooij, Ph.D., and Xaviera Plas-Plooij are a father-daughter team. Dr. Frans has researched parent-baby interaction for more than 35 years. Xaviera is a Wonder Weeks expert and mother of three. Their child development books, available in 16 languages, have sold more than two million copies worldwide.