“The only time I hear them,” John Delaney remarks of the 120 antique American tall-case clocks crammed into his West Townsend, Massachusetts, gallery, “is when they stop.” It has often been said that the steady ticktock of a classic timepiece resembles a heartbeat, and the tall-case—also known as the grandfather or, in Britain, the long-case—has other features that evoke the human body, from stylized feet to painted face. (The American composer Henry Clay Work gave the tall-case its nickname, referring to “my grandfather’s clock” in a popular 19th-century ditty he wrote that was inspired by one in the lobby of an English hotel that kept perfect time until the two elderly brothers who owned it died.) “It is the only living piece of furniture you can own,” says the Massachusetts-based collector Todd Keating, who has eight of them.

Collectors of the imposing, finely crafted antique tall-cases are attracted not only by their decorative beauty but also by the “extra value” provided by their unseen works. “Collectors of fine furniture will buy the finest clocks as both furnishing and horological pieces,” says the Sotheby’s London horology expert Jonathan Hills. “The market for golden-era long-case clocks has never been stronger.”

The tall-case clock was a luxury item and was therefore made in major cities throughout Europe, where demand was high and the clientele sophisticated, according to Emily Eerdmans, of New York’s Hyde Park Antiques, which specializes in 18th- and 19th-century English furniture. Auction bidders favor examples by such 17th-century British makers as Daniel Quare, Thomas Tompion, Joseph Knibb, Edward East and Henry Jones, acknowledged as the supreme masters of their trade, along with the American grandfather clocks from this period, which were largely modeled on their British counterparts. Antique Continental floor clocks, especially those from France and Holland, also have enthusiasts, mostly among the French and Dutch. Although London is the traditional center of the antique clock market, many people see the tall-case as a piece of furniture, and that view has made them at home in the various European furniture sales held in New York and Paris as well, says Christie’s horology specialist Jamie Collingridge. Although Geneva is a prominent center for the watch market, he adds, the Swiss were not big clock makers.

A Dutch mathematician and physicist, Christiaan Huygens, is credited with being the first, in 1656, to use a pendulum as a regulator, replacing less-accurate mechanisms. Both the English and the French were quick to adopt this innovation. But it was a Londoner, William Clement, who perfected it and is commonly regarded as the father of the grandfather. Clement’s enhancement, introduced around 1670, was the anchor escapement mechanism, which allows for longer, slower pendulums and more precise timekeeping. Technical advances like that, together with exceptional workmanship, placed British clock makers at the forefront of the industry throughout the tall-case’s heyday, which lasted until around 1730. The French, on the other hand, were renowned for ornate clock cases, which often echoed the sculpture and decorative objects of the period.

Today, says Sotheby’s Hills, prices for antique tall-case clocks “range from a few hundred dollars for a poor example up to $3 million for the best 18th-century French example.” In the million-dollar category is a tall Louis XVI ormolu-mounted ebony grandfather, made in 1774, that was sold at Christie’s in July 1999 as part of the collection of the brothers Albert and Nathaniel von Rothschild, of the storied banking dynasty. It made £1.93 million ($3 million), roughly three times the estimate of £500,000 to £800,000—an unprecedented price due in large part to the clock’s impressive provenance, prime condition, pleasing proportions and, significantly, stunning gilt-bronze embellishments, including flower-head-festooned guilloche bands, fruiting laurel flutes and wreath and a flaming-urn crown with foliate sprays. Also important to its valuation, however, were the esteemed craftsmen associated with it: Balthazar Lieutaud, who made the case; Ferdinand Berthoud, the movement; and Philippe Caffiri, the mounts.