Foreword 



There is but one safe \\'ay to avoid mistakes: to do nothing or, 

 at least, to avoid doing something new. This, however, in itself, 

 may be the greatest mistake of all. The selected, who are able to 

 open new roads to science without erring, are very few and the 

 author, certainly, does not belong to them. The unknown lends an 

 insecure foothold and venturing out into it, one can hope for no 

 more than that the possible failure will be a honorable one. 



One of the most characteristic features of present-day biochem- 

 istry is the coexistence of highlights with darkness, knowledge 

 with ignorance. While we can perform reactions that amount to a 

 "miracle" and, here and there, even improve on nature, we can- 

 not answer many of the simplest and most fundamental questions. 

 We have, for instance, detailed information about the structure of 

 the protein molecules but cannot tell why nature has put those 

 atoms together in that highly specific way, what was the quality 

 she wanted to achieve by doing so. The same holds true for nucleic 

 acids and nucleoproteins. We know most hormones, and many of 

 them we can build ourselves outside of the living body. In a few 

 cases we can even produce more active agents than nature did. But 

 how hormones act, what they do on the molecular level, we do 

 not know; we have not gone beyond symptomatology in the analy- 

 sis of their action. The same holds true for most of our drugs. 



The same duality exists also in our knowledge relating to the 

 high-energy bonds, the main representative of which is the high- 

 energy phosphate bond P — O — P, "^^P." Their discovery belongs, 

 undoubtedly, to the most brilliant achievements of modern bio- 

 chemistry. We know how, at the expense of one -^P, another 



