As someone else said, "Operation World is one of the most important Christian books in the world because it mobilizes the church to reliably informed intercession."
Jesus commanded his disciples, "Look, I tell you, lift up your eyes, and see that the fields are white for harvest" (Jn. 4:35). At this point the disciples were not thinking about harvesting people, much less the despised Samaritan people group. But later, by the help of the Holy Spirit they did "lift up their eyes," and catch a vision for reaching the ends of the earth with gospel of their Risen Christ!
Over the years, through using this resource in private prayer and in our family worship God has "lifted up my eyes" to the harvest and given me bigger vision both for what God is doing and the vast needs that still remain among the 7 billion people in this world. This book has not only informed me about gospel work, but has reminded me often that I server a BIG God who is doing GREAT things in HIS world. I often feel the wonder of the privilege it is to be apart of this unstoppable mission through informed prayer! I heartily agree with the words in the preface of this book, "Each and Every prayer is a tiny piece of a great cosmic puzzle, which when fitted together will allow for the completion of the grand picture of the Almighty Lord's plan for humanity and the universe. We don't merely pray ABOUT the many points featured herein, we pray TOWARD something, and that something is magnificent - the fulfillment of the Father's purposes and His Kingdom come."
I recommend to you, if you know Christ and long for His kingdom to come, get a hold of this book, read it, pray it, and trust that one day you will meet people in heaven who are there because you prayed. Who knows, God may even call you or others in your family to go make disciples in one of these places."From William Carey's 'Enquiry' of 1792 to Operation World today, God has worked mightily across the centuries through statistics and maps, using them to propel men and women of faith and devotion to the places on earth" (p974)
Lastly, I also want to recommend the abridged version of this book, "Pray for the World" (April 2015). I recently stared using this smaller book (331 instead of 978 pages) and found it ideal for praying through the nations as family. Not only is the content abbreviated to about one page per country, but they organized the countries alphabetically by region. So instead of praying for Argentina and Armenia back to back (in Operation Wold), you pray for Argentina and Brazil back to back in this book. This helps provide a geographical context especially with kids.