Atlas - Craftsman12-inch Lathe Late Model - Post 1957: These had various Model Numbers starting with "39" and including: 3950, 3965, 3975, 3980, 3981, 3982, 3983, 3985, 3986, 3996, 3720, 3990, 3991, 3995, 3975.
The Craftsman version (in all respects identical to the Atlas) were usually marked: 101.28990, 101.28950, 101.28910, 101.28940 or a similar 101.289** number including: 101.2758, 101.2759, 101.2895N, 101.2893N, 101.2894N, 101.2897N, 101.28990, 101.28991N and 101.28993N2.
To be sure that you're ordering the right manual, my article about these lathes is here late-model 12-inch Atlas lathes here.  If unsure, you can see the earlier 10-inch type on this page.
Blown up from its original small size to twice as large (A4 11.5" x 8") and printed on a high-quality, heavy paper and68 bound in two volumes for easier reading and clearer diagrams, this is a complete data pack of information that covers all models, from the first to last. It includes:
1) A comprehensive Owner's Manual with over 240 pages that contains detailed operating instructions for the lathe and its accessories together with maintenance and lubrication instructions - it's probably the best instruction book ever produced by a lathe manufacturer.
2) Extensive thread-cutting instructions and dedicated charts from the larger 61-page "supplementary" Screwcutting Instruction Booklet.
3) Extra instructional sheets issued by Atlas but never included in the main manual: taper turning attachment; fitting new leadscrew nuts, steady rests, adjustable bed stop, machine vice and dismantling procedures for headstock and backgear.
4) A complete illustrated parts list with exploded-parts diagrams.
5) A set of reproductions of the original advertising catalogs (some very rare) that give a complete technical specification for the lathe, shows model changes over the years. All the accessories are shown - enabling easy identification of any items that might be found on the second-hand market.
A large and heavy publication. Printed as a very high-quality reproduction on 120g paper and bound (it's a weighty volume enlarged to A4 size, that's just short of "letter"). A large and heavy publication. Available as either a bound, high-quality print at £75 or £45 with the original high-resolution files on a Pendrive (though the online system still says CD-ROM). To check the price in US dollars visit: http://www.xe.com/currencyconverter/ A customer responds: What a stunning product this manual is.  I did consider a CD-ROM but as my lathe has served for over 60 years and my computers don’t last 10 years, well, you work it out. You’ve done a great job, I had an idea of what to expect from my Fobco book but this is on another level.  When I’ve worked out what my other old lathe might be I’ll be back. Meanwhile thanks again. Good book, good packaging and good delivery. Yet another very satisfied customer. Bill Stone