In 1902 Walter Blackie, of the publishing firm Blackie and Son, was building a family home in Helensburgh. His art director, Talwin Morris, suggested he work with a young Glasgow architect named Charles Rennie Mackintosh. Blackie had a few requirements. He wanted grey rough-cast walls and a slate roof rather than the brick, wood beams, and red tile that were common in the west of Scotland. He wanted architectural effect achieved through the massing of forms rather than applied ornament. Within those constraints, he gave Mackintosh creative freedom. Blackie later recalled that Mackintosh worked with the family closely throughout, tailoring the layout to their daily routines. "Not until we had decided on these inside arrangements," Blackie remembered, "did he submit drawings of the elevations." The house was designed from the inside out.

The total fee for Mackintosh's work was £5,000, a substantial sum but one that covered both architect and craft. Margaret Macdonald Mackintosh played a central role in shaping the interiors — she designed custom furniture and decorative elements, and her gesso panels and stained glass appear throughout the house. Some interpretations of the design suggest it reflects Edwardian gendered associations of interior space with femininity and exterior form with masculinity. Mackintosh deliberately complicated that division, introducing elements normally associated with the latter into the domestic interior, departing from the heavily ornate style that conventional Edwardian taste expected. Different rooms feel atmospherically distinct according to their intended function: the public spaces formal and rectilinear, the private spaces softer and more intimate.

Mackintosh chose Portland cement harling for the exterior walls, an innovative material for 1902 but ultimately a flawed choice. Traditional Scottish harling uses lime, which is porous and lets water pass through and evaporate. Portland cement traps moisture instead. Water entered the walls from the outset and could not get out. As early as 1953, then-owner Campbell Lawson commissioned the Glasgow architect Margaret Brodie to investigate; she identified the large chimney stack at the west of the house as the most likely source of ingress. The same chimney was flagged again in 2019, when an infra-red thermographic survey mapped where moisture had penetrated. By 2017 the building's deterioration had reached the point of threatening structural integrity. Something serious had to be done.

In 2019 the National Trust for Scotland enclosed the entire house in a transparent, chainmail-clad structure. The Box, as it is informally called, is itself a remarkable piece of architecture: porous walls that let air circulate while shielding the building from rain, internal walkways that allow visitors to view the Mackintosh exterior from elevated viewpoints they could never reach otherwise. The idea is simple: keep the rain off long enough for decades of trapped moisture to evaporate, then begin proper conservation work. Current plans have the Box remaining in place until 2028. Visitors get a strange, unprecedented chance to see a Category A listed building from the air, walking around its roofline at eye level, while specialists work to save it from itself.

The Blackie family lived in the house for decades. In 1982 it was donated to the National Trust for Scotland, which has cared for it ever since. The Trust continues to maintain it and open it to the public — even now, with the Box overhead and conservation work ongoing, visitors come from around the world to see what Mackintosh and Macdonald built together. According to local paranormal accounts, the house is reputed to be haunted by Walter Blackie himself: a tall figure in a black cape, the smell of cigar or pipe smoke in rooms where no one is smoking. Whether you believe in ghosts or not, the building has always exerted a strong hold on visitors. It is, after all, one of the rare surviving Arts and Crafts houses where the architect's full vision — exterior, interior, furniture, fittings — was realised more or less complete.