MONTREAL - The sweet, subtle sounds of the violin waft through Tom Wilder's office. Stringed instruments, their wooden bodies burnished to a deep hue, sit in racks waiting for their owners to pick them up and make beautiful music once again.

In a downstairs workshop, a skilled craftsman hunches over a cello on his bench while another makes minute adjustments to the bridge of another instrument, carefully sizing and sanding the part.

The ancient art of stringed instrument repair and restoration can be an incredibly complex and painstaking craft.

"We've worked on instruments for years, replaced wood grain by grain," said Wilder, who in 1991 founded Wilder & Davis Luthiers Inc., one of the foremost stringed instrument makers and restorers in North America.

The shop has worked on some of the most renowned brands in the world, including legendary Stradivarius instruments such as a cello valued at about $8 million.

"It's really case by case," Wilder, a 52-year-old Torontonian now based in Montreal, explained when asked about the restoration process.

"Sometimes it's a repair that takes 15 minutes. If it's a repair that's more complex, we could work for months or years on the same instrument. If it's been eaten by worms, if there are hundred of cracks, it's going to take a long time to repair."

Using plaster casts to restore the instrument's shape and replacing interior wood are some of the efforts to bring the instrument back to life.

"It's very, very complex," Wilder notes, adding that reputable restorers can be found through the American Federation of Violin and Bow Makers and the Entente internationale des luthiers et archetiers.

Some of the instruments make their way to Wilder's shop after being discovered in attics and basements but the majority come from players around the world.

Wilder & Davis has another workshop in Banff, Alta., and has also worked in Winnipeg, Calgary, Vancouver and Edmonton.

Clients have included the musicians of the Montreal and Winnipeg symphonies.

Besides repairing and selling stringed instruments, Wilder and his team evaluate instruments, which is a key part of the restoration process. A lot depends on how the instrument is to be used. If it's not going to be played, it may not be worth the expense of restoring it.

"Sometimes it's not always a good idea in fact to restore an instrument," said Wilder, who has worked in the United States, France and South Korea.

"It may be too valuable because in the course of restoring something you're replacing original material. Other restorations are done for the wrong reasons, just for esthetic reasons, which is probably not a good idea."

Sometimes the sound can change.

"We like to think we know what we're doing and that we can sort of predict how it's going to turn out but in fact that's not always the case," Wilder said.

"Sometimes we're pleasantly surprised, sometimes disappointed."

The sound can change because wood is being replaced and parts of the instrument that may have sunk because of the pressure are being reshaped.

"In doing that we have to reinforce it with material from the inside and sometimes that can have a dampening effect on the instrument."

The considerations that go into restorations are among the topics in another of Wilder's efforts, "The Conservation, Restoration and Repair of Stringed Instruments and Their Bows." The ambitious set of books documents the craft and is one of the most definitive works on the subject.

The idea for the volumes came after Wilder attended a conference on stringed instrument restoration and the participants mused it would be good to put all that knowledge in one place with the proceeds being donated to charity. It took 10 years to put together and cost more than $1 million.

The exhaustive three-volume set, which has 1,600 pages and more than 1,300 illustrations, prompted a group of British students to start a fundraising effort so they could buy a set for their school.

Cost per set? $1,395.

The students, who attend a violin making school, are crafting a handmade instrument to be given to a talented needy student. They are asking their community to donate money to cover the instrument's cost, which will be used to buy the books.

The books, which came out last year, are another linchpin in preserving a time-honoured craft that goes back centuries and flies in the face of the plethora of electronic gizmos musicians use to crank out sound.

"We've really tried to present the different techniques but within a context of either environmental or theoretical or historical issues that have to be considered when selecting the technique or performing the technique (for restoration)," Wilder said.

Aurele Parisien, who managed the production of the books, says the decision was made to self-publish because the subject is too specialized and the market too scattered for a regular publisher.

"I've overseen the publishing of about 285 books in my time but this is by far the biggest and most complex project that I've managed," he said.

"This book is about the best practices in craftsmanship so it was crucial to us that we had to exercise the best practices in making the book."

Everything about it is environmentally friendly, from the paper to the inks to the labour practices at the plant where it was printed, Parisien says.

The environment also played into the decision to self-publish because a regular publisher would have only paid royalties.

The creators wanted to pull in the sales themselves, not to reap a huge profit but to raise money to save the endangered pernambuco tree, which has provided wood for bows for more than 250 years.

"The best bows have come from this wood," said Wilder, who hopes the book will break even by the end of the year. He hopes to contribute $400,000 to pernambuco conservation during the next decade.

Parisien adds the book has a triple conservation angle going for it.

"It's saving instruments, it's saving trees and saving craft practices all at the same time," he said.