In 2015, Prof. John Barclay wrote Paul and the Gift (Eerdmans), an important monograph that rocked Pauline studies and has widely been hailed the most important book on Paul in the last two decades.
In 2020, Barclay will publish another book on the theme of grace. From what I can gather, this book revisits and summarizes his key arguments (it is much shorter than PatG), and Barclay engages with the critical feedback he has received in the last few years. If you read Paul and the Gift, you will be interested in the way Barclay responds to the ongoing conversation about Pauline theology. If you did not read Paul and the Gift, this book will serve as a nice condensed summary (it would seem).
The title of the new book is Paul and the Power of Grace (Eerdmans, Nov 2020).