This is a vintage original WWII era manual on using oxygen equipment in bombers published by the 2^nd A.F. Altitude Indoctrination Unit at the Lincoln Army Airfield in Lincoln, Nebraska.   This manual is a booklet format of 64 pages plus the covers measuring about 5” x 4”.  The front cover is titled:

Restricted – Survival at Altitude for Heavy and Very Heavy Bomber Crews – Prepared By 2^nd A.F. Altitude Indoctrination Unit L.A.A.F. Lincoln, Nebr. 

The inside front cover is printed “Notes On the Use of Oxygen Equipment in the B-17, B-24 & B-29 For Combat Crews” 

This booklet has several photographic illustrations and drawings and lots of detailed information for training bomber crews on using the oxygen equipment on B-17, B-24 and B-29 bombers during WWII.  The back cover is printed “1-25-45” which I take to indicate a January 1945 publication date.  This manual is fully complete and intact with some toning and minor faint spotting to the covers.  Overall condition is very good for this vintage original.