Good question, but it must be known that the UB (or the Urantia Papers)
was not brought forth by what we commonly know today as 'channelling' or a like phenomena,...but a unique process and some ascpects that are unexplainable (perhaps near 'miraculous'), in as much as has been recorded or revealed by those closely associated with the 'process' whereby they 'materialized'. Authorities of the UB emphatically claim it was not 'channeled' or brought about by means commonly associated with Spiritualism, psychic reading, occultism, etc.
An order of being known as
'mid-wayers' were involved in serving as a 'liaison group' between our world (thru a sleeping subject) also allowing for a higher group of divine sons and celestial personalities to dictate primarily the first 3 parts....such were given permission to give forth the 5th epochal revelation to our planet thru this collaboration.
Besides the sleeping subject there was human participation involved in order to allow the transmission to take place,... a 'forum' of individuals that presented questions to the various celestial personalities who would expound and give answers to those questions, which came forth in a systematic manner as the 'papers' and was organized as we have the UB today,...in 4 parts. I've yet to read a few works about the history of such, but have read some on it. The following links below will help,...plus researching the OP and using the 'thread search' feature in the upper right of the discussion area.
Who wrote the UB? (truthbook.com)
Who wrote the UB? (Meredith Sprunger)
How The Urantia Papers came to be according to The Revelators (Urantia Foundation)
Also, there has been a modern movement within some UB readership groups called the 'Teaching Mission'(TM)...where some people serve as 'transmitters'...which might be more kin to what is modernly known as 'channeling' (in some fasion)...but the Urantia Foundation (the trustee and publisher of the UB) does not accept or endorse TM at all, and holds true to the UB in and of itself being a complete and sufficient revelation given for this dispensation (being the 5th Ephochal revelation to your planet). See
here.
The UB is to be judged by its content, as the message, meaning and values given speak for themselves in their own terms and context. Its a comprehensive cosmology
- feel free to wade thru the thread, and chime in with anything of particular interest.