The hard-working author admitted during an overseas interview that other projects he has ideas for have tended to take a back-seat to the A Song of Ice and Fire series, which sparked the TV phenomenon Game of Thrones.
Five books in that seven-strong series have already been released, with The Winds of Winter – the sixth – having been in the works for several years now.
“I do get a lot of pressure, but most of it comes from within,” he is quoted as saying.
“That is… I want it to be a really great story, and a great story should have a beginning, a middle and an end. So far I have two of three, and now I need to give an end [with] the last two books.
“The fans want it, my publishers want it, but no one wants it more than I do.”
Martin was speaking to Esquire in Russia last summer, in an interview that has resurfaced on Reddit. In it, he also mentioned his other ideas, such as Avalon.
He had said: “Everyone wants these books [ASOIAF], mothers will appear in front of my house with pitchforks and torches, so I dare not do this!
“When I had a vision for the first chapter with Bran, I wrote Avalon, a science fiction novel. But I did not have a contract for it, Avalon was not announced, no one expected it, did not look forward to its appearance: neither publishers nor fans, so I could easily put it aside.
“I have whole boxes full of projects that I started, but I have not finished yet. Avalon is just one of them.”
The Winds of Winter is unlikely to be released in 2018, given that Martin has confirmed another release – the first volume of companion book Fire And Blood – will come out first.
Game of Thrones, the TV show, will finish with its final season in early 2019.