This is a book about eagles because - well, because that is what Jim Crumley does.

As he writes, "because I know eagles, because I see them often, because I admire them, because I thrill to them, because I want always to know more about them and because for the last two years … they had dominated my working days and more or less filled my working hours while I tried to write them down in this book."

Not an introduction, and certainly not an attempted justification, but 107 pages in, he is coming clean, saying it how it is when the author has, perhaps not so coincidentally, found two white-tailed sea eagles observing him on a Perthshire golf course. Frankly, I can't think of many better reasons to sit down and write a book, not so much about eagles, as about the writer becoming an eagle himself.

Despite its recent renaissance in the UK (hooray for that!), nature writing remains an obscure art form. I liken it to an artist limiting his or her work to lino or woodcuts. Nature writers know very well that print runs and sales are likely to be tightly rationed, but that does not daunt writers like Crumley.

"Because I thrill to them" is the giveaway line and it is what makes this book so tinglingly readable and what sweeps the reader up in Crumley's effervescent passion for eagles, for mountains, for the snaking Tay, for the omnipresent and irrepressible nature of his native land.

We exterminated the erne - Anglo-Saxon for sea eagle and the name commonly used in Scotland until mindless extirpation finally removed it from our skies in 1916 - because it had the temerity to be a predator. It possessed that hallmark of all evil, a hooked beak, so vilified by crofters and sheep farmers, by salmon fishers and grouse shooters, by gamekeepers and ghillies and by just about everyone who understood nothing of wildness and saw the Highlands as a place exclusively for humans and not for nature. It was also very easy to kill. Sea eagles are carrion eaters, as well as predators of rabbits and hares, fish and sea birds, ducks and geese, even, as Crumley recounts second-hand, occasionally of swans, which provides an insight into just how powerful this bird is.

Rabbit carcasses laced with strychnine was the means by which many sporting estates and farmers purged their land of ravens, crows, foxes, buzzards, wildcats and, yes, golden and sea eagles. Sadly, it persists to this day, although those who represent sporting interests will insist it is only a rogue few who continue to break the law in this vile and indiscriminate way.

It was the 2007-2012 reintroduction of the sea eagle to the Tay estuary that fired Crumley into following these huge birds across the landscape of his homeland. He pursued them with binoculars every day, plotting their movements, identifying individuals, learning their ways. The Scottish reintroduction of this great raptor started on the island of Rum in 1975 and there are now more than 50 breeding pairs, mostly around the isles of Mull, Skye and the west coast.

The author begins his odyssey in Orkney at the Tomb Of The Eagles on South Ronaldsay and explores vividly the millennia-long connections between people and sea eagles in pictorial archaeology and legend, suggesting that long ago we lived in harmony with these magnificent birds - that human lives were enhanced by that association and that perhaps we could achieve that again. It is a journey that takes him to the Western Isles and Skye and finally returns him to Perthshire, where he theorises that because the Fife eagles came from Norway, they only know west coasts and that some deep sunset-written instinct takes them there still. That is The Eagle's Way - the route they take up Strathtay and over the mountains through to join their numbers well established on the west.

This book will teach you much about eagles, but more than that, Crumley's distinctive voice carries you with him on his dawn forays and sunset vigils, watching the eagles stir from their pine tree roost before dawn and return there in the dusk. You begin to understand that this nature writer is so deeply engaged with nature and the nature of his eagles that he becomes absorbed by them, thinking eagle, acting eagle, becoming eagle himself. It is an intriguing lesson not just in fieldcraft, but also in human and animal psychology.

I have watched eagles all my adult life and I thought I knew them well, but The Eagle's Way lifts me out of that complacency and demonstrates there is so much more to learn.