Apple design chief Jony Ive says his company had no choice but to release a book detailing some of its product designs over the last two decades.

Speaking to cultural site Dazed in an interview published this week, Ive said that the company “had a responsibility to…archive” some of its best designs. He noted that Apple aapl has spent the last eight years developing the book it announced this week, Designed by Apple in California, and felt it was only right to release it to the world.

“Honestly, it felt more of an obligation than something that we felt really compelled to do,” said Ive. “The reason for that, and I guess it’s a fairly obvious one, is that as designers, we are far more interested in and consumed by the future; in what doesn’t exist yet. But we’ve been working together for 20, 25 years, and it felt like the right and appropriate thing to do. You get a sense of what we’ve learned as a team and of how technology is evolving.”

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The coffee table tome details the company’s product design from the 1998 iMac to the 2015 Pencil. While it’s mainly a big picture book, it also includes mention of the materials and design philosophies Apple employed to create its many iconic products. Dedicated to late Apple co-founder Steve Jobs, the book comes in two sizes, priced at $199 for the smaller version and $299 for the bigger option.

In a statement accompanying the book, Ive said that he wanted it to be “a resource of students of all design disciplines.” In his interview with Dazed, which was earlier discovered by 9to5Mac, he explained in more detail the design philosophy that he believes, makes Apple’s products aesthetically appealing.

“What we try to do is get to a point where it seems almost undesigned, where it seems so obvious that an alternative would seem contrived and not rational,” he said. “To get to that point of that ‘perceived inevitability’ is extremely difficult.”

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Ive then shifted his attention to other topics, including Jobs, the man for whom the book was made. He said they worked well together and took a holistic approach to design.

“It’s an entire approach, an entire attitude towards the work,” Ive said. “I think it was the all-consuming nature of it being about the product. It begins and ends with the product and if your absolute and complete focus is sincerely to try and make the very best product, then all of the other issues tend to resolve themselves.”