Katje,

Firstly, when matter or energy enters a black hole, the only obvious way out is by black hole "Hawking" radiation (worm holes etc are still a bit speculative, for example, and anything passing through a worm-hole loses most or all of its information anyway.)

It is not even clear that any black hole exists that is small enough to produce significant Hawking radiation.

In general a black hole only grows, no matter what. It doen't "spurt out" anything. I suspect that you may be thinking of the "jets" and similar radiation emitted from a spinning black hole, but those do not come from the black hole, but the "accretion disk" and similar regions in which falling matter interacts. Even if two black holes collide there is no splash, unless you count gravitational waves and so on. 

Therefore, when matter or energy "enters a black hole",  it certainly is not  "spurted out again" in any form, different or not. What is more, even if it does get out by Hawking radiation, it only does so completely anonymously and even indirectly by the random emission of single particles from particle-antiparticle pairs out of vacuum fluctuations. You would need a lot of luck to get information out of that!

You ask whether,  if anything leaves the black hole in a different form, would it be possible, theoretically, to say, put back together a book that was sent into the black hole? Firstly, as you can see, it doesn't, won't, and therefore isn't! 

Consider: imagine that I handed you a vessel containing powdered salts and carbon dioxide and assured you that it was all that remained of a copy of either "Mein Kampf" or "How to Win Friends and Influence People" that I had burnt completely. How would you tell which it had been, or even whether I had lied to you and it had been the contents of an office waste paper basket? 

Compared to whatever you could scrounge from a black hole, my vessel would be full of information!

Sorreee... the short answer looks like the right answer, I should say.

And the short answer was NO!

Cheers,

Jon

Regarding Jon's mention of Hawking radiation, this only allows a black hole to shrink if the hole's radiation temperature is greater than the cosmic background radiation's temperature (2.7K).  Smaller holes have higher Hawking temperatures; holes lighter in mass than the moon will radiate.  All larger holes will grow, so they won't lose information via this radiation.

When matter falls into a black hole, only its mass, charge and momentum are conserved (visible to an outside observer).  But since quantum mechanics forbids the loss of information, where that information goes and what ultimately becomes of it are still topics of discussion, debate, and the betting of fine bottles of wine and sports dictionaries (the latter being a case where information is retrievable whenever one wishes).

It's been shown mathematically that the surface area of the event horizon is directly proportional to the information content that a black hole has swallowed, and the forms of the equations that describe and measure information are essentially identical to those in thermodynamics describing entropy.  The two concepts are deeply and beautifully related in some way.