Systematic Theology (Wayne Grudem)
A big "book of everything" that serves as more reference material than daily reading, Systematic Theology is still a great read for worship leaders. It serves as a constant reminder of the depth of God and His Word - something that worship leaders sadly neglect in favor of more emotion-based works.

Worship Matters (Bob Kauflin)
Among worship leaders, Kauflin's practical, easy-to-read collection is a standard. You'd be hard pressed to find a worship leader who hasn't read this book! This book manages to communicate sound Biblical teaching and worship philosophy with real world application and lots of great stories from Kauflin's rich career of worship leading and pastoring in the local church.

Worship By The Book (D.A. Carson)
A great, expansive treatise on the importance of approaching corporate worship from a holistic perspective - allowing God's Word to be the focus and source of learning and worship. The book features numerous writers (many from more mainline denominations) but still manages to stress the importance of scripture in our services.

Music Through The Eyes Of Faith (Harold M. Best)
Not an easy read, but a worthwhile excursion. The author assesses and explains the role of music from a Christian worldview, but also goes to great lengths to pinpoint Godly truths in all of culture and music. Harold M. Best has a real knack for metaphors and stories that back up his sweeping statements.

Mirror Ball (Matt Redman)
Redman's books read like his songs - he manages to write both plainly and poetically - somehow stating big truths beautifully without making the reader grab for a thesaurus in the process. This is not a book about music; it's about a lifestyle of worship. It's a fast read, but a good solid reminder of what God asks of us. There's a substantial discussion guide provided in the back of the book. Perfect for small group or band devotionals.

The Art Of Curating Worship (Mark Pierson)
In an attempt to show all the different ways people "process" spiritual experience, the book (intentionally or not) minimizes the role of scripture. The stories and practical explanations of creative ways of engaging people are extremely helpful, but the book seems to be more focused on feelings than actual truth.

Engaging With God: A Biblical Theology Of Worship (David Peterson)
It's a heady book, with lots of Greek and Hebrew, which is difficult. However, the care taken to analyze worship from Old Testament to New Testament is captivating. Great takeaways from this book, specifically how the role of the temple changed over time and what it means in our current context. A great read for worship leaders who want to have a better mental picture of what's most foundational about worship.

Common Roots: The Ancient Call To An Ancient-Future Faith (Robert E. Webber)
The book functions almost like a prequel, revealing that the author was thinking through the melding of old and new long before he became a best-seller in the 1990's. The book operates from a simple premise - the modern day church has left its historic roots. It's not an argument for traditionalism, but it does act as a "measuring stick" that puts beliefs and practices of today alongside the historic church.

Real Worship: Playground, Battle Ground or Holy Ground (Warren W. Wiersbe)
Wiersbe speaks from years of pulpit experience and manages to speak from solid doctrinally footing without checking his emotions at the door. This book may be one of the most balanced perspectives on worship you'll read and it's a convicting message about trusting human planning over God's Spirit. 

Rhythms Of Grace (Mike Cosper)
Essentially an entire book that aims to teach us to model the Gospel completely in our worship services. There's good, solid advice here and some sample set lists to show all the different ways the message of the Gospel can be presented during corporate worship. A good read for young worship leaders.

Imagining The Kingdom - How Worship Works (James K.A. Smith)
This book is long, and maybe a bit redundant, but it's worth a look. Smith doesn't necessarily agree that people make important decisions based on intellect alone. The book redefines "imagination" as it relates to spiritual experience and builds a case for the ability of liturgy to re-fashion what people care most about. Fascinating (and a bit tiring) read.