电子版序言
Preface to the Electronic Edition
本电子版于 1994 年根据一部无版权的 1962 年 Image Books 版扫描而成。全文和部分脚注已予复制。近 1000 条说明各手稿差异的脚注（以及脚注的一部分）已被省略。脚注中的页码引用，在可能处已改为章与节。本版已校对一次，但可能仍有其他错误。
This electronic edition was scanned in 1994 from an uncopyrighted 1962 Image Books edition. The entire text and some of the footnotes have been reproduced. Nearly 1000 footnotes (and parts of footnotes) describing variations among manuscripts have been omitted. Page number references in the footnotes have been changed to chapter and section where possible. This edition has been proofread once, but additional errors may remain.