A succinct history of wool dye classes in the 20th century is followed by a review of the Lanaset dyeing system by Ciba-Geigy with its use of 1:2 metal complex and reactive dyes. A discussion of the isoelectric point (pH 4.9 at 20°C, pH 4.6 at 90°C) emphasizes the need to minimize fiber damage by processing in the proper pH range. -- AATA