The next several paragraphs describe in detail the differences between the eight known significant revisions.  After the first five, they tell when the revisions occurred. The section on each version begins with the version ID number that will be used in the version number to machine model published as a separate document. Note that this ID number does not appear on any MOLO and that the acronym "MOLO" was created by the author of this document.

Prior to 1955, all versions of the MOLO say on the copyright page just "Copyright 1937". There is no edition number and no print history.

A recently acquired Atlas Catalog No. 25 contains a photograph of the then current Atlas MOLO.  It shows a book that may have either black or dark blue covers and that is exact bound (glue and staples).  It does not have the familiar outside micrometer printed on the cover, has slightly different text printed, and has an APC (Atlas Press Company) logo printed.  No copy of this version is known to exist.  So in the interest of not causing confusion, it will be assumed that the contents are the same as in the version identified as 1937V1. And will be called 1937V0.

1937V1:  The photographs used in the second 1937 version are mostly of the Atlas lathe commonly known today as the Atlas 10D. More correctly, some could be of any model from 10 through 10E.  The name "Atlas" appears fairly frequently throughout the book, both in text and captions.  Chapter 7, Threading, applies to the Atlas 9" and to the Atlas 10" up through the 10E (all that were equipped with change gears with a 96T gear included) and a lead screw).  With due consideration to the fact that the reversing tumbler gears aren't shown on the Threading Chart, it is also applicable to all lead screw equipped early Craftsman 12" machines (i.e., those that used 96T change gears). This includes any Atlas Utility or Craftsman Universal models fitted with optional change gears and lead screw sold in 1936 or 1937. This version (with the exception noted above) is full length wire bound and has blue covers with the same information printed on the front as on all of the later ones, except that there is no Atlas logo.

1937V2 (Atlas) and 1937V3 (Craftsman) 2.   For several years, Sears Roebuck & Co. had been selling the Atlas 9" lathes under the Craftsman badge.  In 1936, Sears began selling the Atlas built Craftsman 12".  In 1938 Atlas was getting ready to introduce the F-Series 10", more commonly known today as the 10F. And no doubt Sears had been pushing them for a Craftsman version or at least one that directly covered the 12" and didn't advertise Atlas. So the first revision to the MOLO probably occurred in 1938 or 1939. Many of the 10D photographs in 1937V1 were replaced with 10F ones.  The lubrication chart photograph was changed from a 10D with vertical countershaft to a 10F with horizontal countershaft and other photographs of the horizontal one were added.  All pages were removed from Chapter 7 - Threading.  In place of the2 Without the loose Threading Supplement originally supplied, the two versions are actually the same.
bound-in Chapter 7, the manuals shipped with Atlas lathes included a revised but separate (loose) Threading Supplement covering the Atlas 10F. The manuals shipped by or bought from Sears included a Threading Supplement covering the Sears Master Craftsman 12" with the tumbler type reversing mechanism. Both cover the later change gear train (wider "A"-suffix gear hubs and only up to 64T). Unfortunately, these supplements are usually missing or the seller doesn't know that they belong in the manual.  In Chapter 8 - Attachments, several photos (carriage stop, steady rest) were replaced with photos of the later versions. For others, (tool post grinder, milling attachment), some photos were replaced and some added.   Also, except on the front cover, the Title Page, and in the 10F Threading Supplement, the word "Atlas" was redacted and replaced by generic text such as "the lathe". This version is wire bound (some full length, some with two separate lengths of wire, and some with three), all covers are black with the Atlas logo on the front, and the Copyright page still says just "Copyright 1937" (no edition number), and below that "Price One Dollar" is added. The photos on page XII are changed and the caption is changed from "Atlas-Equipped Shops" to "The Modern Lathe In Operation".
There is evidence that these versions were still being shipped from stock after the next two versions came out.

1937V4 (Atlas) and 1937V5 (Craftsman):  The next two versions, one for Atlas and one for Craftsman, probably came out at the same time. The date of introduction is currently unknown but was probably 1939 or 1940. There is evidence that one of these was supplied with a new Craftsman lathe as early as 1941. The only major change from the previous two versions is that the appropriate Threading Supplement is bound into Chapter 7 - Threading.  But the Supplement is still paginated as 1 to 61, and the remaining page numbers are the same as in the previous two versions.  Both versions still have the Atlas logo on a black front cover.  The binding was originally wire.  It was soon changed from wire to white plastic so most existing copies are with plastic binding. Apparently around the same time that the binding was changed, the "Price One Dollar" was removed from the copyright page. Other minor changes are that an ad for a wall chart entitled "The Modern Back-Geared Screw-Cutting Lathe" is added on the previously blank page facing the tabbed divider for Chapter 1. And the "9 - Woodturning" tab is changed to "9 - Woodworking".  At least the last two of these changes weren't done immediately as what are assumed to be early copies don't show either change.  But most presumably later printings do.
These two versions (V4 and V5) were issued up through 1954.

1955V6 (Atlas) and 1955V7 (Craftsman):  The fifth and sixth versions came out in 1955 as the Sixteenth Edition.  Binding is still white plastic.  The Atlas version has a gray cover.  The Sears version cover is still black but "CRAFTSMAN" replaced the Atlas logo on the front. The copyright page now says "Sixteenth Edition" (in both versions).  For the first time, the cumulative Reprint history is shown on the copyright page, beginning with 1938 and ending with 1955. The copyright line just says "Copyright", not "Copyright 1937" or "Copyright 1955".  If you count the years listed and add 1 for 1937 you get 18, not 16. Someone miscounted.  In Chapter 1 - The Lathe, the Lubrication Chart is redone from a photograph and chart to 8 drawings.  And the recommended oil viscosity is changed from SAE 10 to SAE 20 except one place in the text.  The lubrication drawings in both versions are of the Atlas 10F and the subtitles say Atlas 10 Inch. They also show the QCGB, which for this purpose is almost the same on the 10F and the two Craftsman models.  As in the previous versions, except in Chapter 7 - Threading, all photos are of the Atlas 10" machines. Coverage of babbit bearings is removed
along with any mention or photo of the vertical countershaft.  Instructions for removing the back gears and Timken spindle are added.  A couple of the photos of lathe parts made from Zamak are moved or changed.  Page count up through Chapter 6 remains the same and Chapters 2 through 6 are the same as in the previous two versions.  In Chapter 7 - Threading, a Table of Contents for Chapter 7 is printed on the divider tab.  Chapter 7 through the end of the manual is repaginated. The Atlas version Chapter 7 mentions Atlas and the Craftsman version mentions Sears in most of the appropriate places.  All photos are of the appropriate lathes (Atlas or Craftsman). A section is added covering the QCGB models. For the first time, a 6" section is added, along with the only 6" photo ever to appear in the MOLO. The photo in the Craftsman version is of the Atlas 618 but there are only minor differences in this view between it and the then current Craftsman 101.07301.  From Chapter 8 on, the two versions are the same as the previous two except for the repagination and the following.  A few more of the older version attachments are dropped or replaced by later versions.  The clamping plate for the milling attachment is deleted and the bed turret added.  The tab for Chapter 9 - Woodworking is changed back to 9 - Woodturning. From the Reprint history shown in later editions, these two versions were only printed in 1955.
V8:  The eighth version came out in 1957 as the Seventeenth Edition. The only difference between the Atlas and Craftsman versions is either a gray Atlas or a black Craftsman front cover so they are being counted as one version, not two.  With the exception of some that show specific machining or accessory operations (and thus not machine model specific), most photos were replaced by ones of the new and heavier 12" now being sold by both Atlas and Sears.  Where visible, all photos show just the "Atlas" badge.  In Chapter 1 - The Lathe, the spindle and back gear sections are changed to cover the new headstock with internal back gears.  The paragraph on the spindle Indexing Mechanism wasn't added until the 1960 printing. Chapters 2 through 6    are the same as in the 1955 versions.   In Chapter 7 - Threading, drawings and photos are changed to ones of the new heavier 12". The words "Atlas" and "Sears" are again redacted.
TEN-INCH is changed to 12-INCH and 10" is changed to 12".  In Chapter 8 - Attachments, a few more old-version photos are deleted. The Tool Room Taper Attachment is removed and additional instructions added for the newer version. The remainder of the manual is initially the same as in the previous 1955V5 and 1955V.  In 1961, the following minor changes were made, but are not being called a version change. The wall chart showing the 10F Lathe is changed to the set of five charts showing V-Type Threads, etc.  In Chapter 1, SAE 10 in the text is changed to SAE 20.  In Chapter 8, two photos of a drum switch with an extension operating rod are changed to eliminate the rod.  And in Chapter 9, descriptions and photos of the tee hand rest and the woodturning face plate are deleted. There are no changes to page numbering.
V9:  The ninth and final version came out in 1967 as the Twenty-third Edition, at the same time as the introduction of the final version of the 12" lathe. Again, there are gray Atlas and black Craftsman covers.  Most pertinent photos were changed to ones showing the lever cross feed operator, new lead screw slip clutch, and/or new right lead screw support and thrust bearing.  In the front of the manual, the wall chart ad moved to the back of the TOC, the preface was shortened and the photo of a bench model lathe replaced by one of a cabinet model. As an aside, the part of the preface that was deleted implied that Atlas lathes were inexpensive and didn't cost "several hundred dollars" like their high priced competitors. J In Chapter 1 - The Lathe, Fig. 9 was changed from one of a 10F in a 1940's machine shop to one showing probably a 3996 with collet attachment in use.  Fig. 20, which had been a detail of the carriage apron (and which was actually off of a 10F) was deleted.  The paragraph on Zamak parts was deleted.  Chapters 2, 3 and 4 are unchanged.  In Chapter 5 - Holding Work, Fig. 87 (3-jaw chuck) was cropped (for no apparent reason).  In Chapter 6 - Drilling, Fig. 109 (Drill Grinding Attachment) was replaced with an uncaptioned photo of an Atlas 398x with steady rest mounted and a drilling operation in progress.  The text, photo and drawing at the end of Chapter 6 offering a blueprint for making a boring bar was deleted.  In Chapter 7 - Threading, the short section and photo on electrical coil winding was deleted.  In Chapter 8 - Attachments, the text and photo on gear cutting, including a blueprint offer, was deleted. Figs. 238, 239 and 240 showing grinding operations were deleted and replaced by one that is uncaptioned. Fig. 242 showing dressing the grinding wheel was replaced with one showing the later grinder. All text and associated photos on grinding valve stems, valve seat cutters, and valve guide reamers were deleted.  Fig. 257 (grinding a 60 deg. center) was deleted but not the associated text. All mention of turret lathe related attachments was deleted. Chapters 10, 11 and 12 are unchanged. There were no changes in the content of V9 over the period 1967 to 1988.
The preceding paragraphs primarily concentrate on material added to and/or deleted from the previous MOLO version to make the new versions 2 through 9. The next three pages contain the Index from MOLO Version 9.  Aside from page number changes due to adding or deleting material over the years, there is little difference between the index for the final version and the ones for the previous versions.  It will thus give a good idea of what the text in all 9 versions contains.

The fourth page back shows two cutting speed tables that are found in the MOLO.  The exact spindle RPM required is rounded off to the nearest of the 16 speeds actually available on all of the Atlas or Atlas built lathes that have a countershaft and back gears.  Following the speed charts is a list of the tables found in Chapter 7 - Threading and Chapter 10 - Tables.