Who and what are BEL/Bell Labs amplifiers


I have noted several times the existence of a company called BEL or BELL Labs and their amps seem to be geared towards the high end market, and yet, I cannot find any sort of information about them, just the fact that they sometimes appear in the used market. What sort of company is or was BEL/BELL and what is the typical sound and look of their units. Are they simply a relic or are they just some very well kept secret. Is there are website with detail description of them?
bemopti123
I own the first production BEL 1001. It has serial number 0001. How's that for rarity! I bought it from the original owner.I am planning to use it with my Quad 57's. 
I own a BEL1001 MK V made in 2007. It is the most prized component in my system. I found it used at a dealership in Chicago. Should (when) it needs servicing I am not sure where I will take it, however will look into it.
I have a pair of BEL MK V's that were tuned to each other as monoblocs by the late Mr. Brown.  I will keep these in my system until either they or I die, whichever comes first! They are the best sounding most balanced amps I've heard (been in this hobby for 25 years).