The collection includes:
1. The rare book library bequeathed by Kenneth K. Mackenzie in 1934 to the Horticultural Society of New York, sold to Robert de Belder in 1981.
2. Robert de Belder's other acquisitions, including the library of Philippe de Vilmorin; a number of books from the Boissier-de Candolle collections (disposed of as a result of the amalgamation of those two libraries in the Conservatoire Botanique de Genève); significant auction purchases of a number of books from the sale of the Arpad Plesch collection (de Belder being the single largest buyer), as well as at sales from the libraries of the Earl of Derby, the Linnean Society of London and the Massachusetts Horticultural Society.
3. The present consignor's acquistions, augmenting nos. 1 and 2 above. These comprise the best selection of the finest color-plate books from the de Belder library (sold, Sotheby's London, 27 and 28 April 1987) as well as significant later additions made from worldwide sources in the international book trade and at public auction.
The provenance designation: "Kenneth K. Mackenzie; Horticultural Society of New York" in lots containing a single title has been abbreviated to "KKM/HSNY" in group lots. Since all of these items were later acquired by Robert de Belder we have not continually used his name to avoid repetition. All of the books from Mackenzie's bequest bear a discreet library blindstamp in the lower blank margin of one text leaf, as well as a bookplate.
Exception is made, however, when the present consignor purchased a Mackenzie book from the de Belder sale at Sotheby's 1987 sale. In such cases the provenance designation in the present catalogue shows "Robert de Belder" followed by the sale details.