The French architect-engineer Pierre François Henri Labrouste (1801-1875), a major innovator in the field of cast-iron construction, was a leader of the romantic-classicist school of architecture.

Henri Labrouste was born in Paris on May 11, 1801. At the age of 18 he entered the École des Beaux-Arts as a pupil of A. L. T. Vaudoyer and L. H. Lebas. In 1824 Labrouste won the Grand Prix de Rome and studied Roman construction at the Villa Medici (1825-1830). While in Italy he produced a controversial restoration of the temples at Paestum (1828-1829); his account of the restoration appeared in Les Temples de Paestum (1877). On his return to Paris he opened a studio at the École des Beaux-Arts and became a leader of the rationalist school of thought, which opposed the traditional eclectic approach to architecture of the period.

Among Labrouste's earliest works are an asylum for Lausanne, Switzerland, won by competition (1837-1838), and a prison for Alessandria, Italy (1840). His first major commission, the Bibliothèque Ste-Geneviève in Paris, came in 1839 (built 1843-1850). This long, oblong masonry structure in the romantic-classicist tradition of early-19th-century French, English, and German architecture was innovative in itself. In addition, it incorporated a light cast-iron structure as a roof-support system. Sixteen slender cast-iron columns, of proportions to be found only in Pompeiian wall paintings, divide the long space into two barrel-vaulted naves; the barrel vaults consist of interlaced wires covered with layers of plaster, supported on delicately scrolled arches springing from the columns.

The reading room and the stacks Labrouste added to the Bibliothèque Nationale in Paris (1858-1868) continued the developments begun at Ste-Geneviève. The roof of the reading room is supported on 16 columns, 32 feet high and only 1 foot in diameter. This grid of columns supports nine shallow terra-cotta domes, each with an oculus and with no lateral thrusts to the exterior walls. Beyond a large glass opening from the reading room is an even more functional stack area, five stories high, including a basement. Natural light from the glass roof filters down through cast-iron "cat-walk" gratings. Bridges link the circulation areas from one stack to another.

Labrouste's attitude to design is summed up in a quotation from Souvenirs d'Henri Labrouste (1928): "In architecture, form must always be appropriate to function.... A logical and expressive decoration must derive from the construction itself." He died at Fontainebleau on June 24, 1875.