This fourth volume of Advances in Computer Graphics gathers together a selection of the tutorials presented at the EUROGRAPHICS annual conference in Nice, France, Septem ber 1988. The six contributions cover various disciplines in Computer Graphics, giving either an in-depth view of a specific topic or an updated overview of a large area. Chapter 1, Object-oriented Computer Graphics, introduces the concepts of object ori ented programming and shows how they can be applied in different fields of Computer Graphics, such as modelling, animation and user interface design. Finally, it provides an extensive bibliography for those who want to know more about this fast growing subject. Chapter 2, Projective Geometry and Computer Graphics, is a detailed presentation of the mathematics of projective geometry, which serves as the mathematical background for all graphic packages, including GKS, GKS-3D and PRIGS. This useful paper gives in a single document information formerly scattered throughout the literature and can be used as a reference for those who have to implement graphics and CAD systems. Chapter 3, GKS-3D and PHIGS: Theory and Practice, describes both standards for 3D graphics, and shows how each of them is better adapted in different typical applications. It provides answers to those who have to choose a basic 3D graphics library for their developments, or to people who have to define their future policy for graphics.

The term differential-algebraic equation was coined to comprise differential equations with constraints (differential equations on manifolds) and singular implicit differential equations. Such problems arise in a variety of applications, e.g. constrained mechanical systems, fluid dynamics, chemical reaction kinetics, simulation of electrical networks, and control engineering. From a more theoretical viewpoint, the study of differential-algebraic problems gives insight into the behaviour of numerical methods for stiff ordinary differential equations. These lecture notes provide a self-contained and comprehensive treatment of the numerical solution of differential-algebraic systems using Runge-Kutta methods, and also extrapolation methods. Readers are expected to have a background in the numerical treatment of ordinary differential equations. The subject is treated in its various aspects ranging from the theory through the analysis to implementation and applications.

Past Matters brings together a group of largely Australian and New Zealand academics who in a series of case studies consider how planning concepts were adopted, adjusted, adapted and extended in a Pacific Rim setting. The early chapters explore the interplay between British and American planning models and local circumstances in Australia, Japan, and New Zealand. The main body of chapters recount difficulties faced by indigenous peoples with respect to housing needs and more generally re-asserting themselves in what began as colonial urban areas as well as others that look at community meanings, liberalism and exclusion on the street, and the power of sectional interests. The latter chapters also pose questions about urban heritage in terms of what and whose interests are at stake in these debates. The volume concludes with two convergent chapters that outline some practices by which `heritage' of a more day to day suburban sort can be protected within a planning system. The collection centres on Australia and New Zealand but extends to include chapters on Canada and Japan. The viewpoints offered serve as a gentle reminder of the limitations of `Metropolitian Theory'.