You might be interested in some threads from the WWII FAQ section on "The atomic bombs":

Did the Atomic Bombings or the Soviet Invasion of Manchuria make Japan surrender?

• There has been some controversy on the true effect of the atomic bombing of Japan. Was it the bomb, or the Soviet declaration of war that ended WWII? - 19 comments, over 2 years old.

• The commenters in this thread showcase the arguments made by in favor of the Soviet influence on the Japanese surrender using diary entries of the Japanese officials and other records that previously had not been looked over in analysis of the issue.

• Why did Japan surrender? - 33 comments, over 2 years old.

• This thread goes into several criticisms of Hasegawa's conclusions regarding the Japanese surrender.

• Are Tsuyoshi Hasegawa's conclusions about the Soviet's influence in triggering the Japanese surrender of WWII widely accepted or are they in dispute? If he got it wrong, how did he get it wrong? - 27 comments, over 2 years old.

• This thread not only gives further criticism of Hasegawa but details how he has been received in the historical community.

Overview of the Atomic Bombings

• In "Did the US *have* to nuke Japan in WWII?" /u/restricteddata comment on the topic here - 6 comments, less than 1 month old.

• A flaired specialist on the topic gives a summary of the topic, including the decision making process, the context under which action was taken, common misconceptions, and essential literature on the matter.

• Could America have used the atomic bomb on a purely military target or some other more ethical way to force Japan's hand into peace? - 118 comments, over 2 years old.

• The commenters here lay out the issues as considered by US officials at the time.

• Why was an invasion of Japan or the dropping of the atomic bombs argued to be necessary for Japanese surrender in World War 2? - 25 comments, over 9 months old.

• A user flaired for the subject matter weighs in with an overview of the strategic situation and comments afterwards discuss various recommended books giving contrasting views on the subject as well as the importance of the unconditional surrender that had been demanded by the Allies.

• Why didn't Japan surrender after the first atomic bomb? - 500 comments, over 2 years old.

• The topmost commenter gives a big overview of the issue, talking about both the decision to use the atomic bombs and the Japanese reactions as well historiographical debate on the bombings' motive and importance.

• Would the Japanese have likely agreed to total unconditional surrender after just a "warning shot" pf the atomic bomb? - 36 comments, over 2 years old.

• The commenters in this thread address the mentality of the Japanese high command in the days just before the atomic bombings.