Describing and designing complex electronic systems has become an overwhelming activit)' for which VHDL is showing increasingly useful and promising support. Although created as a description language. VHDL is being increasingly used as a simulatable and synthcsizablcdcsign language. For the first time, here is abook which describesa number of unique and powerful ways VHDL can be used to solve typical design problems in systems -- ones which must be designed correctly in vcry short periodsoflime. Typically useful lcchniquessuch as switch-level modeling, mixed analog and digital modelling, and advanced synthesis for which VHDL showsgrealpromisearefully presented. Thesemeth- ods are bOlh immedial.ely applicable. and indicale lIle potential of VHDL in efficiently modelling Ihe real worldofelectronic systems. Sinceitsinception.there hasbeen adesireforananalogdescription languageconsistent with (and integrated with) VHDL. Until recently. VHDL could onl)' be applied to digital circuits.ootlhedreamofdescribingandsimulatingmixedanalogand digitalcircuitsis now a reality as described herein. Describing the functionality of analog circuits including intetoperability with digital circuits using the VHDL paradigm is surprisingly easy and powerful. The approach outlined by the authors presages a significant advance in the simulation of mixed systems.