ALVAN LAMSON - THE CHURCH OF THE FIRST THREE CENTURIES = A MUST READ!
Alvan Lamson's book:
"The
church of the first three centuries, or, Notices of the lives and
opinions of the early Fathers, with special reference to the doctrine
of the Trinity, illustrating its late origin and gradual formation." 1880.
Is a must read.
Heres the link to read it online for free:
http://www.archive.org/stream/churchfirstthre02lamsgoog#page/n6/mode/2up
He was a Unitarian who did not believe in the Trinity nor the pre-existence of Christ, but his book is full of very interesting information on the earliest Post-Biblical Christian writers.
Enjoy!