There are six new booklets available from The Gospel Coalition in this very helpful series.
The Kingdom of God by Stephen Um
The Gospel and Scripture: How to Read the Bible by Mike Bullmore
Sin and the Fall by Reddit Andrews
Justification by Philip Graham Ryken
Baptism and the Lord's Supper by Thabiti Anyabwile and J. Ligon Duncan
Christ's Redemption by Sandy Wilson
About the Gospel Coalition: We want to generate a unified effort among all peoples—an effort that is zealous to honor Christ and multiply his disciples, joining in a true coalition for Jesus. Such a biblically grounded and united mission is the only enduring future for the church. This reality compels us to stand with others who are stirred by the conviction that the mercy of God in Jesus Christ is our only hope of eternal salvation. We desire to champion this gospel with clarity, compassion, courage, and joy—gladly linking hearts with fellow believers across denominational, ethnic, and class lines. (Excerpted from their Preamble)