Bob May was born Sept. 4, 1939, and Bob Tufeld on Dec. 11, 1926, so they were 26 and 40 on the day Lost in Space debuted.
He is an environmental control robot (The Reluctant Stowaway).
In earlier episodes, the Robot can sing. But he sings "Tiptoe Through the Tulips" very badly in Space Circus.
The Robot's name is GUNTHER (General Utility Non-Theorizing Environmental Robot) (The Thief of Outer Space).
He studied pre-medicine at the Institute of Cybernetics for two semesters, and was first in his class (Kidnapped in Space). He majored in law at IPT (Fugitives in Space).
He is made of a titanium steel alloy (The Time Merchant).