## Perspectives in Logic

The Perspectives in Logic series publishes substantial, high-quality books whose central theme lies in any area or aspect of logic. Books that present new material not now available in book form are particularly welcome. The series ranges from introductory texts suitable for beginning graduate courses to specialized monographs at the frontiers of research. Each book offers an illuminating perspective for its intended audience. The ASL is committed to making books in the Perspectives in Logic series available at a reasonable cost, and intends to keep them available in print or electronic form indefinitely.

This series is the successor to the series Perspectives in Mathematical Logic, which was founded in 1969 by the Omega Group, consisting of R. O. Gandy, H. Hermes, A. Levy, G. H. Müller, G. E. Sacks and D. S. Scott. This group was initially sponsored by a grant from the Stiftung Volkswagenwerk and the series appeared under the auspices of the Heidelberger Akademie der Wissenschaften. From 1986 to 2001, Perspectives in Mathematical Logic was published by Springer-Verlag under editorial direction of the Association for Symbolic Logic. In 2001 the ASL assumed full responsibility for the series and broadened its scope to include all of logic. It is now published jointly with Cambridge University Press as Perspectives in Logic.

This site has electronic versions of the early volumes from the Perspectives in Mathematical Logic series now owned by the ASL. Information about the series including editorial policies and submission information can be found at www.aslonline.org/books_perspectives.html.

Editorial Board

Chapter I: Constructive Ordinals and $\Pi^1_1$ SetsHigher Recursion Theory (1990)