THE King James Bible, Guinness Book of Records or The Da Vinci Code could all reasonably be expected to be found in any all-time list of best-sellers.
But after passing the millionth copy mark, a slightly more obscure book, which is not even available in most shops, is now on its way to being recognised as one of the most successful books ever written.
The Pony Club's Manual of Horsemanship, which was first published more than 50 years ago, has long been compulsory reading with anybody with an interest in the animals.
It has enjoyed almost blanket sales success among the equine fraternity, and has consistently been a bestseller for half-a-century.
Normally available from saddling shops, or from branches of the Pony Club, the book's revised and updated 13th edition was launched in the summer.
And now the club, which compiles and edits each new volume, is celebrating selling the millionth copy of what has become an institution around the world.
Equestrian writer Anwen Francis said the book had long been an indispensable part of her library, and that of any keen rider.
She said, "I would imagine anybody with an interest in horses owns a copy and, apart from perhaps top racehorse trainers and top dressage riders, we all find it useful on a regular basis.
"In fact it's the most useful book there is for horsey people.
"I've had my copy since I started riding when I was about six.
"I've wasted loads of money since then on horsey books, but pretty much everything I could have needed has been in the manual.
"It's got all the information you need to pass pony club exams, and most of the information you need on British Horse Society exams as well.
"What's good is that it's so easy to understand, even if you're quite young, but it's just as useful to adults.
"If there's something wrong with your horse, you can check what to do before calling the vet out.
"It's just handy to have in any stable or tack room."
The book covers all essential aspects of horsemanship in its 448 pages. An amalgam of expert knowledge and experience from anyone knowledgeable enough to contribute, it was originally based on cavalry guidelines.
The Pony Club, which aims to encourage young people to learn riding and other activities with horses, deliberately keeps the book simple enough for children to be able to understand. It is now sold in 16 countries.
Mary Anderson, chair of the National Pony Club, said, "Selling as many books as we have is great, but it's no surprise at all the manual's done so well.
"It's sold to all the pony clubs affiliated to us in 16 countries around the world, as well as there being 44,000 members in the UK who probably all own a copy.
"It's a complete instruction on how to look after a pony or horse.
"That means it is something any young rider is going to want to have.
"These days there are so many parents who aren't really horsey people, but whose son or daughter is mad keen. The book is vital to them.
"It's deliberately kept simple so it can be understood by very young riders, but it is something adults are always consulting.
"People join the Pony Club as young as four-years-old, but often stay until they're 23 or 24.
"Most will use the book and buy updates long after that."
Page 2 - Words of wisdom from the Manual of Horsemanship