For this conference, he authored "Left-Wing" Communism: An Infantile Disorder, a short book articulating his criticism of elements within the British and German communist parties who refused to enter their nations' parliamentary systems and trade unions; instead, he urged them to do so to advance the revolutionary cause. The conference had to be suspended for several days due to the ongoing war with Poland, and was relocated to Moscow, where it continued to hold sessions until August.
At a gathering specifically organized for this occasion, he penned "Left-Wing" Communism: An Infantile Disorder, a brief publication detailing his criticism of factions within the British and German communist parties that rejected entering their respective countries' legislative bodies and labor unions; in contrast, he urged them to join these institutions as a means of advancing the revolutionary movement. The conference was temporarily halted for several days due to the ongoing war with Poland, and was subsequently relocated to Moscow, where it resumed its sessions until August.