 So let me summarize the challenges. We have been trying to sign a bit for you. It turns out that there are several stages. First, I mentioned that we have to target something. We need that target ID, target identification. And I won't repeat that. That would be the receptor that I'm interested in. But in addition to the target, I need a smart idea. Something to start with. Start with something. And we typically call that a hit. As you will see later today, we're increasingly finding those hits with computers. But this could be divine inspiration, or that you found a particular plant that has something you want to work with. It's very rare that the starting point is good enough. So this is just working material. We're going to need to ask ourselves, does it have effect? Or is that effect good enough? Or does it have the right effect? It's not obvious in many cases. This is iterated with the next point. Optimize the effect. And that could, for instance, mean purify the molecule so that we don't need to eat so much of it. Can you make the molecule smaller and more efficient? Can you make sure that we don't have side effects or something? So this can frequently go have to be iterated for 20 steps or so. Once you have something that you're starting to really believe in, then we should first do chemistry tests, so-called in vitro tests for glass tube. And once you're happy with the vitro tests, we're going to do in vivo, but in vivo in the sense of animal tests. Typically, first starting with rats or mice or so, and eventually turning onto chimpanzee. Somewhere here, you're starting to be really confident in your drug if all these things have gone well. And incidentally, this is typically where you see things posted in general media that there is this new drug that forces, that enables you to run longer or get rid of a cancer or something. That's very nice if you're a rat. The problem is that most of you listening to these lectures, I presume, are not rats. And because you're not rats, there are a couple of additional steps we need to go through. The first one is phase, what I call phase one. And phase one is the first phase of clinical testing. And then we usually ask one, we just ask one question, is it safe? We could not care less whether it has any effect. It just means will you, will bad things happen if I eat this? The rat didn't die, but maybe I will. Second, then we have, sorry, seven. Then we have the so-called phase two. Is it efficient? And again, both these are related to inhumans. And then we get to the final phase three. Is the efficacy better? Better than what? Better than the alternatives already on the market. In general, we will not approve a drug today unless it is better than we already have on the market. Because this is not just a marketing bullshit game, right? That if your company B and your drug is not as good as the drug that is already on the market, we will not allow it. This leaves out one important last step here that is not really your job, but somebody else's job, FDA or EMA approval. FDA stands for Food and Drug Administration and EMA is the New European Medical Association. So in Europe, we typically do this jointly. This is an exceptionally important step that has appeared the last few decades. And that is simply a way for the authorities to double check that you have done all your homework. If you're a pharmaceutical company and have invested hundreds of millions of dollars here, you have an exceptionally strong incentive to get things on the market. This is a safety check. This is somebody double checking you and making sure have you really looked at all the side effects. We're going to want to look at all your results, make sure that you haven't forgotten anything. There's a famous example of this that saved the United States, but not Europe. So the Food and Drug Administration was earlier with these approvals, but there was pretty much a single officer at the FDA that decided on her own that she was not happy with the tests on Thalidomide. The Thalidomide is the scandal that erupted in Europe that's what Neurosidon, that it was given as a pain-controlled drug to pregnant women, the North Sea during pregnancy, right? Unfortunately, this drug went over to the fetus and made hundreds of thousands of babies in Europe be born without arms or legs or very short limbs at least. Thalidomide was never approved in the U.S. because this officer at the FDA, she was not happy with the tests. The company behind this, they went furious and they tried to have her fired. You can imagine what then happened when they realized that she saved tens of thousands of Americans from very severe birth defects. This was the start of the modern pharmaceutical testing and this is why FDA and EMA today are so rigorous with testing. We don't necessarily trust the pharma companies in everything they say.