Bill D - and anyone else interested:

INFO: Technical Details of TrueType Fonts (KB Q85202) includes a link to the Microsoft Typography site where you can obtain the "True Type Font Specification (400 pp.). On the Typography Site, select "Specifications" under the Developer Tools heading.

The "TrueType" and "TrueType Open" specifications are listed as "for historical interest only," as TrueType has been superceded by the "Open Type Specification. I would recommend downloading the OpenType Specification .zip file (1.5 MB) as otherwise you have to download individual chapters one at a time. The TrueType specification has apparently been "absorbed into" OpenType, and there are a couple of chapters specific to TrueType, and a couple of Appendices that contain Adobe "compact fontfile" info.

My primary reference on Type 1 Fonts is the Adobe Type 1 Font Format, Version 1.1, Adobe Systems Inc., Addison Wesley Publishing Co, Inc., ISBN 0-201-57044-0. My copy shows $14.95 US. A few Specs are available at the Adobe site, and I believe this is one you can download, but I haven't looked recently - 'cause I already bought the book.

I haven't had much of a look at the OpenType thing, but the old TrueType Spec, and the Adobe Type 1 Spec make it fairly clear that a fully defined "Font" is a "single entity" that should be usable on any kind of machine. The Adobe spec, in particular, makes it clear that Macs impose "additional" requirements, but a "complete" font should include everything required by either PCs or Macs. The obsolete TrueType Spec showed a similar "Mac extensions requirements" section.

There is the problem of the reversed byte order between PC and Mac, so it might be presumed that the Mac would need to "read in" the font as a PC-byte-order file(?) if it's a download. A Font is a program, and as such, must be "installed" to be functional. In Windows (98 & later), copying a TrueType font into the Windows\Font directory is all that's required for installation.

Type 1 fonts (and Type 3 - another useful one) generally require a font manage of some sort in Windows, and it would be safe to assume that something similar is required for a Mac. The Adobe ATM is excellent, but is not the only thing around. You can probably find a freeware utility - I haven't checked on the ATM price recently, but my last upgrade was about $80 US (well worth it in my case), so I would guess a new buyer would be looking at $150 or so.

I plead total ignorance with regard to font installation on the Mac. It seems that if we really want to know anything about that, we need an expert Mac driver to comment.

The Advance Systems description of the fonts is fairly accurate, but leaves out some of the details. An example:
Type1 fonts don't contain as much information as TrueType fonts do. Kerning is not stored in the font.

The Type 1 font probably contains more information than the TrueType (one of the reasons for the "new" OpenType spec is to put more in) but when installed (e.g. in Windows) the font is "split" to make it easier to manage kerning and leading under the control of the page layout operator to an extent not readily achievable with TrueType.

But the main concern here seems to be only with the TrueType, so w.t.h...

John