"Thrilling tales of the great west, told primarily for boys but which will be read by all who love mystery, rapid action, and adventures in the great open spaces.
The Manley Boys, Roy and Teddy, are the sons of an old ranchman, the owner of many thousands of head of cattle. The lads know how to ride, how to shoot, and how to take care of themselves under any and all circumstances.
The cowboys of the X Bar X ranch are real cowboys, on the job when required but full of fun and daring--a bunch any reader will be delighted to know." - Grosset & Dunlap advertisement.

This Stratemeyer Syndicate series was authored by several different writers, Leslie McFarlane, Roger Garis and Walter Karig among others.

ILLUSTRATORS
Walter S. Rogers (1-10)
J. Clemmons Gretter (Gretta) (11-15)
Paul Laune (16-21)

This series was published by Grosset & Dunlap and was issued in two binding styles: first gray, then (circa 1932) red, both with full color DJ's and glossy frontispieces. This series was issued without subtitles.

01 - The X Bar X Boys On The Ranch - 1926
02 - The X Bar X Boys In Thunder Canyon - 1926
03 - The X Bar X Boys On Whirlpool River - 1926
04 - The X Bar X Boys On Big Bison Trail - 1927
05 - The X Bar X Boys At The Round-Up - 1927
06 - The X Bar X Boys At Nugget Camp - 1928
07 - The X Bar X Boys At Rustlers' Gap - 1929
08 - The X Bar X Boys At Grizzly Pass - 1929
09 - The X Bar X Boys Lost In The Rockies - 1930
10 - The X Bar X Boys Riding For Life - 1931
11 - The X Bar X Boys In Smoky Valley - 1932
12 - The X Bar X Boys At Copperhead Gulch - 1933
13 - The X Bar X Boys Branding The Wild Herd - 1934
14 - The X Bar X Boys At The Strange Rodeo - 1935
15 - The X Bar X Boys With The Secret Rangers - 1936
16 - The X Bar X Boys Hunting The Prize Mustangs - 1937
17 - The X Bar X Boys At Triangle Mine - 1938
18 - The X Bar X Boys And The Sagebrush Mystery - 1939
19 - The X Bar X Boys In The Haunted Gully - 1940
20 - The X Bar X Boys Seeking The Lost Troopers - 1941
21 - The X Bar X Boys Following The Stampede - 1942

In volume 21, "The X Bar X Boys With The Border Patrol" was advertised as the next title but was never published.