Keys to the Deeper Life is a collection of theological essays written by American pastor and writer A.W. Tozer. Originally printed in Christian Life magazine, these essays ask the faithful to reject worldliness and instead return to "New Testament Christianity" where they will find a "deeper life" and greater connection to God.

A.W. Tozer (b. 1897, d. 1963) was called to Christianity as a teen. One day while walking home from his job at a tire factory, he reportedly heard a street preacher say, "If you don't know how to be saved...just call on God, saying 'Lord be merciful to me a sinner.'" He did as the preacher said upon his return home.

Tozer was one of the most widely-read Christian authors of his time, which becomes understandable when one experiences his simple, layperson style of writing. He was also a powerful preacher. When asked by one of his mentees how he prepared a sermon, he replied that he simply prayed, and God showed him which scriptures his congregants needed to hear.

Keys to the Deeper Life, Tozer's 8th book published in 1957, is a short collection of essays to help contemporary Christians to build a deeper spiritual connection with God and their faith. A common theme throughout his writing is the worldliness of modern Christians, at the expense of the "deeper riches of life."

The four essays in this work are:

● No Revival without Reformation

● The Deeper Life, What Is It?

● Gifts of the Spirit: Are They for Us Today?

● How to Be Filled with the Spirit

In No Revival without Reformation, Tozer argues that rather than seek a revival of the church by increasing its numbers, Christians must reform their lives first and give new obedience to God's commandments. He writes, "We must return to New Testament Christianity, not in creed only but in complete manner of life as well." And he did not leave himself out of this judgement: "And this applies to this writer and to this magazine as well as to everyone that names the name of Jesus."

The Deeper Life, What Is It? expresses concern about his contemporaries' satisfaction with an average spiritual existence, and instead exhorts the faithful to "explore the depths of the Christian evangel for those riches it surely contains but which we are as surely missing."

In Gifts of the Spirit: Are They for Us Today?, Tozer states that there are so few Christians who "want to experience whatever God has for them within the context of sound New Testament faith" that they are easy to overlook. But there are still a few who will welcome these spiritual gifts (including faith, gifts of healing, prophecy, and distinguishing between spirits, among others). And only those who are blessed "by the Spirit through gifts He has Himself implanted in the souls of redeemed men" can do God's eternal work.

In his final essay, How to Be Filled with the Spirit, Tozer outlines the necessary path to fulfillment. First, one must be certain it is possible to be so filled. Then, he must desire to be. This is no simple desire. The person must enthusiastically renounce the control of their life, and cede their personality and "self-sins" to the Spirit. Only when they surrender fully will they be prepared to be filled with the Spirit.

Tozer's reliance on prayer and scriptures to support his writing makes his work simple yet profound, and as relevant now as it was during his lifetime.