There are many books on the market that aim to introduce the seeker to the basics of Druidism, but The Druid's Primer by Luke Eastwood is perhaps the single best introduction book I have read. It's greatest strength is that it manages to present a great deal of modern Druidic material fairly and with clear references to the sources. The author has done a great deal of research into the historic material, which is also presented well and in an easily accessible manner.
The book begins with a chapter that summerizes the historic material. This was very well done, with the material being covered thoroughly but concisely. This section touches on everything from the early Celtic period and what we have from seocndary sources such as Pliny and Caesar up to the modern era revival. Although not gone into as deeply as in other books the single chapter effectively summerizes the highlights and is more than enough to get a beginner started or serve as a basic refresher for a more experienced person.
The next chapter tackles possibly the most complex subject in modern Druidism, defining what a Druid is. The book does an excellent job of presenting the different current theories fairly, including the possible etymologies of the word "druid" itself. The different historical sources are once again drawn upon including Irish mythology and the later Barddas, which the text acknowledges as a well known forgery but also influencial on the revivalist period. The author also discusses his own view of what a Druid does and who a Druid is, creating a fascinating and complex picture of the modern Druid.
From here the next 7 chapters discuss: Gods & Goddesses, Myth & Legend, Elemental Forces, Cosmology, Inspiration, Imramma, and Animism & Animal Worship. Each chapter is a blend of well-researched history and modern application that manages to offer a balanced view of modern Druidism without favoring any one particular path or focus. In most cases multiple views are offered for the reader to consider with sources given so that the reader may further pursue anything of interest.
This is followed by a section, Cycles of the Sun, Moon and Earth, that looks at the historic and modern way that Druids would honor the passing of time and holy days. The author discusses a system of lunar rituals based on Alexei Kondratiev's book the Apple Branch that could be used by modern Druids seeking to connect to the moon. This is followed by a discussion of the solar year and it's holidays, including all of the eight holidays of the modern pagan wheel of the year.
Next is a section on tools, which looks at the tools historically attributed to the Druids. It begins by discussing clothing, rather in depth, including the colors likely worn and the Irish legal texts refering to dress and color. Sickles, wands, staffs, the Druid egg, cauldron/chalice, magical branch, musical instruments, the crane bag, and sword are discussed. The four treasures of the Tuatha de Danann are also mentioned in a modern context as tools that Druids today may choose to use, although they have no historic basis in that context.
The final four chapters look at divination, the Ogham, medicine & healing, and justice & wisdom. Each of these was important in some way to the historic Druids and so each chapter looks at how the subject relates to historic Druidism and how these can relate to modern practice.
Overall this book is more than worth the money and certainly the best book to begin with if one is interested in learning about the path of Druidism. It is full of the history of Druidism and also shows the wide array of modern possibilities that are open to new seekers. For more experienced Druids this book will serve as a great refresher or reference.