The revelation was made by the former President in his recent book "Turning Points: A Journey Through Challenges".
He said his decision to decline the Cabinet position enabled him to contribute to two major programmes that gave "spectacular" results to the nation.
Kalam, who was then the DRDO chief, recalls that he got a phone call on the midnight of 15th March, 1998 from Vajpayee.
"He said that he was finalising the list of ministers and he wanted to induct me into his cabinet. I told him that I needed some time to think about it. He asked me to see him the next morning at 9 AM."
Kalam said that in the middle of that night he assembled his few friends and debated up to 3 AM whether he should join the Cabinet or not.
The general opinion was that since he was fully involved in two missions of national importance and these were in advanced stages and nearing good results, he should not leave them and enter the political system, he said in the book.
"The next morning, I went to 7 Safdarjung Road, where the PM was staying....I then told him, 'I and my team is busy with two important programmes. One is readying the Agni Missile system and another is bringing to a close the nuclear programme through a series of tests in partnership with the DAE (Department of Atomic Energy)'.
"I feel that by involving myself full time with these two programmes, I will be contributing more to the nation. Please permit to continue," Kalam said.
Vajapyee responded by saying he appreciates Kalam's feelings and told him to go ahead with his task.
"I appreciate your feelings. Go ahead, God bless you," Vajpayee responded, the book says. (MORE)
