I've been doing this challenge since 2013 (my best year so far) and I have no idea where I came across it first but I mentioned in an old post that there is a group on Shelfari called 'Read the Alphabet' where you can find the rules if you are interested. I mostly just do this as a personal challenge. It helps keep my titles a little diversified since it's really easy to end up reading tons of books that start with 'The'.
Here's my progress so far:
(CR) = Currently Reading
A
B
C
The Canterville Ghost by Oscar Wilde
Casual Vacancy by J.K. Rowling (CR)
D
Dorothy and the Wizard of Oz by L. Frank Baum
The Death Cure by James Dashner
E
The Emerald City of Oz by L. Frank Baum
F
Fable: Blood of Heroes by Jim C. Hines
G
H
I
J
The Jungle Book by Rudyard Kipling
K
The Kill Order by James Dashner
L
The Library of Souls (#3) by Ransom Riggs
M
The Marvelous Land of Oz by L. Frank Baum
The Mark of Athena by Rick Riordan (CR)
N
North and South by Elizabeth Gaskell
O
Ozma of Oz by L. Frank Baum
The October Faction (#1) by Steve Niles
P
Paper Towns by John Green
The Patchwork Girl of Oz by L. Frank Baum
Q
R
The Road to Oz by L. Frank Baum
S
The Second Jungle Book by Rudyard Kipling
The Scorch Trials by James Dashner
Silver in the Blood by Jessica Day George
Serafina and the Black Cloak by Robert Beatty
T
Trigger Warning by Neil Gaiman
Tik Tok of Oz by L. Frank Baum
U
V
W
We Were Liars by E. Lockhart
The Winner's Curse by Marie Rutkoski
The Wonderful Wizard of Oz by L. Frank Baum
X
Y
Z