Multiple Master (MM) typefaces were an interesting experiment in digital typography. Created by Adobe, MMs dispensed with the usual system of font weights (bold, semibold, regular, bold, etc) in favour of smooth variation in the axes of weight, width and optical size. Many more variations were therefore available than could be achieved with a standard family of typefaces.
Adobe released several attractive and useful typefaces in this format: Cronos (see image below), Bickham Script, Chapparal, Myriad, Minion, Ocean Sans and others. However, the sheer time and expense involved in creating MM typefaces meant that other type designers were slow to come on board, and eventually Adobe allowed the format to lapse in favour of Open Type (in the context of the bigger debate surrounding the harmonisation of True Type and Type 1). Adobe has released a collection of 'equivalent' Opentype typefaces with a slew of additional characters, but they don't fully recapture the range of subtle variations that characterised the MM format.
Adobe released several attractive and useful typefaces in this format: Cronos (see image below), Bickham Script, Chapparal, Myriad, Minion, Ocean Sans and others. However, the sheer time and expense involved in creating MM typefaces meant that other type designers were slow to come on board, and eventually Adobe allowed the format to lapse in favour of Open Type (in the context of the bigger debate surrounding the harmonisation of True Type and Type 1). Adobe has released a collection of 'equivalent' Opentype typefaces with a slew of additional characters, but they don't fully recapture the range of subtle variations that characterised the MM format.