The series was an extension of DC's Limited Collectors Edition, which began the short-lived but memorable trend of tabloid-sized reprint comics; Marvel's Treasury Editions were also an expression of this idea. These large-format comics collected stories from past comics, often with short additional features created for the edition; some contained all-new material (like Jack Kirby's Bicentennial Captain America Treasury for Marvel) but for the most part nearly all tabloid-sized comics were composed of reprinted stories.
The Famous First Editions were differentiated by reprinting the first issues of DC's most celebrated comics, or the issues introducing important characters (such as Batman in Detective #27).
The Famous First Editions included:
C-26: Action Comics #1
C-28: Detective Comics #27
C-30: Sensation Comics #1
F-4: Whiz Comics #1
F-5: Batman #1
F-6: Wonder Woman #1
F-7: All-Star Comics #3
F-8: Flash Comics #1
C-61: Superman #1
The series also existed in hardcover format, except for F-6 through F-8; the hardcovers came with dust jackets and command higher prices in good condition. The same issues also were printed in editions with two covers, inner and outer; the inner covers were identical to the original comics', except of course for the size.
C-61 also exists in a Whitman-printed variant.