We rated 6 predictions from billionaire Seth Klarman's super-rare 1991 book, which sells for thousands today and is still considered an investing gold standard

• Billionaire Baupost founder Seth Klarman has been one of the most-followed voices in investing for years.
• His 1991 book, "Margin of Safety: Risk-Averse Value Investing Strategies for the Thoughtful Investor," is considered by many to be the seminal text on value investing. It is out of print, and first editions of the book sell online for thousands of dollars.
• In the book, Klarman makes several predictions, some of which now seem prescient while others are clear misses.
• For example, Klarman calls indexing - and index funds - a fad.
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Seth Klarman has built a career and massive fortune on being right when it comes to picking investments.

The billionaire founder of Baupost Group is one of the world's most-followed investors, and has grown his hedge fund to more than $30 billion in assets since it was founded in 1982.

But even Klarman cannot see into the future, as several remarks from his out-of-print book "Margin of Safety: Risk-Averse Value Investing Strategies for the Thoughtful Investor" show. The book, which resells online for thousands of dollars, is considered one of the most important investing books out there, and details Klarman's approach to value investing.

Despite the massive size of his fund, Klarman keeps a relatively low profile and rarely gives interviews. That combined with the scarcity of the book has helped contribute to its lasting allure.

The ability of value investors to consistently outperform has also become a hot topic in recent years as a surging market has pushed up nearly every stock, not just the companies seen as the best deal.

Other hedge funds, like Steve Mandel's Lone Pine, are questioning if companies viewed as value bets should still be considered a bargain, or if they are simply unable to keep up with massive, tech-driven structural shifts. Baupost has had muted returns the past couple years, and returned roughly the same as the average hedge fund last year.

The decades-old descriptions of Klarman's thought process and portfolio management techniques contained several comments on what he thought the future would hold, as well as strong stances that were uncommon at the time, but popular now.

Several of the predictions now look prescient, nearly 30 years since the book's publication. Others did not materialize, in part because they did not capture just how much technology would transform the investment industry.

The firm declined to comment. The book notes that investing is an art as much as it is a science, and that no investment can be 100% sure and safe.

Klarman's focus, the book explained, has been on making decisions, projections, and predictions with as much research as he can, while also being flexible to change his prognosis if new information emerges.

And to be sure, Klarman has changed up his outlook in areas outside of investing. The one-time largest donor to the Republican party in Massachusetts has become a leading Democratic donor, and he laid out his issues with the Trump administration to The New York Times ahead of the 2018 midterm elections.