Foreword

Chemistry began with magic. Who but a wizard could, with a puff of smoke, turn one thing into another? The alchemists believed that the ability to transform materials was a valuable skill, so valuable in fact that they devised complex descriptions and alchemical symbols, known only to them, to represent their secret methods. Information was encoded and hidden, suffused with allegorical and religious symbolism, slowing progress. Medicinal chemists today may be particularly interested in a legendary stone called a Bezoar, found in the bodies of animals (if you knew which animal to dissect), that had universal curative properties. I'm still looking. However, to plagiarise a recent Nobel prize-winner for literature, the times they were a changin'. Departing from the secretive "alchemist" approach Berzelius (1779-1848) suggested compounds should be named from the elements which made them up and Archibald Scott-Couper (1831-1892) devised the "connections" between "atoms," which gave rise to structural diagrams (1858). In 1887, the symbols created by Jean Henri Hassenfratz and Pierre Auguste Adet to complement the Methode de Nomenclature Chimique were a revolutionary approach to chemical information. A jumbled, confused and incorrect nomenclature was replaced by our modern day designations such as oxygen, hydrogen and sodium chloride. The new chemistry of Lavoisier was becoming systematised. The "Age of Enlightenment" created a new philosophy of science where information, validated by experiment, could be tested by an expanding community of "scientists" (a term coined by William Whewell in 1833), placing data at the core of chemistry.

With the accumulation of knowledge, and a language to communicate chemistry, the stage was set for the creation of a new science of information in the domain of chemistry. Up stepped Friedrich Beilstein (1838-1906), who systematically collected chemical data on substances, reactions and properties of chemical compounds in the Handbuch der organischen Chemie (Handbook of Organic Chemistry, published in 1881). The naming of compounds was a key feature which enabled the storage and retrieval of chemical information on a "grand" scale (1500 compounds). The indexing of chemical information meant chemistry could be reliably stored, common links between data established, and - most importantly - the information could be retrieved without loss. This drive for efficient indexing was the dominant feature of chemical information research for the next half century. As chemistry (and its many related disciplines) continued on an ever upward trajectory of innovation (and data collection) the paper trail required to go from perfectly reasonable questions like "how do I synthesise this compound" to "has this compound been made before" became rather complex and time consuming. I remember many happy hours spent in the library of the Wellcome Foundation trawling through the multitude of bookshelves of Chemical Abstracts to find one compound, and if lucky, a synthesis simple enough that I could perform with a yield better than my usual ten percent. Of course things got worse (or better if you were a librarian), and I recall an interesting RSC symposium in 1994 called "The Chemical Information Explosion: Chaos, Chemists, and Computers." We had clearly reached a point where someone had to invent Chemoinformatics.

Although the "someone" is of course a worldwide community of scientists interested in chemical data, the term was coined by Frank Brown in 1998, and he defined it as "the mixing of those information resources to transform data into information and information into knowledge for the intended purpose of making better decisions faster in the area of drug lead identification and optimization." The combination of multi-disciplinarity, the reduction of data to knowledge and the driving force of the pharmaceutical industry have been key features of the advance of Chemoinformatics. The enabling technologies have been the availability of unprecedented amounts of chemical data (increasingly pubicly available) and the continuous development of new algorithms, designed specifically for chemistry, to achieve the goal of turning information into knowledge. Of course Moore's law (an observation by Gordon Moore at Intel), that the density of computer components (and the computation power offered) doubles every 2 years has underpinned the hardware necessary to keep pace with the data explosion. But perhaps some of the chaos remains, hence the popularity of software such as Babel, which converts many data formats to many data formats!). Some numbers here are interesting. If we recall that the first edition of Beilstein's Handbuch contained 1500 compounds, the Chemical Abstracts Service of the American Chemical Society reported in 2015 that they had registered their 100 millionth chemical substance. What is truly transformational (if you think about it) is that a new student, with a basic knowledge of chemistry, when asked to search for a single compound from the 100M registry, gets the correct result in a microsecond. Not only that, a host of measured and predicted chemical properties, synthesis strategies, available reagents, structurally similar compounds and internet links to a multitude of other diverse, information rich databases.

Clearly, Chemoinformatics has come of age. In fact the term "Chemoinformatics" has gained a certain elastic quality. The methodologies and data analysis tools developed for chemical information have evolved and extended to the data analytics of essentially any data that includes chemistry. Examples include for example, the simulations of large systems of molecules such as proteins, machine learning (and the recent resurgence in Artificial Intelligence) to create predictive models, for example, for metabolism, ADME properties and Quantitative Structure Activity Relationships of drugs (including quantum chemistry, bioinformatics, and analytical chemistry) and the detection and analysis of drug binding sites. Although much of the early work in Chemoinformatics has been applied to problems of the pharmaceutical industry, the subject has been embraced across the sciences wherever chemistry is required for example, in agricultural and food research, cosmetics, and materials science.

But in an age when computers can do "magic," ("Any sufficiently advanced technology is indistinguishable from magic" - Arthur C. Clark) it is tempting to return to where we were in the time of Berzelius and hide the technology behind an alchemical mask of symbols for example, a simple interface which hides highly complex search and retrieval algorithms or a machine learning application to predict metabolism. The antidote to this is of course education. A firm grounding in the principles and practice of Chemoinformatics provides students and expert practitioners alike with the knowledge of the underlying algorithms, how they are implemented, their availability and of course limitations of software for a given purpose as well as future challenges for those with a keen interest in developing the field.

The best textbooks are naturally written from the viewpoint of those who are intimately connected to their subject. The Chemoinformatics group at the Computer-Chemie-Centrum (CCC) at the University of Erlangen-Nuremberg have been pioneers in Chemoinformatics for over 30 years and are recognised as both innovators and experts at applying these methods to a large variety of chemical problems. However it is as educators that perhaps their greatest impact on the field may accrue over time. The new book "Applied Chemoinformatics - Achievements and Future Opportunities" shows the many fields chemoinformatics is now applied to and builds on the successful first edition "Chemoinformatics - A Textbook" (published in 2003) and is again edited by Johann Gasteiger and Thomas Engel. This volume is complemented by an additional textbook "Chemoinformatics - Basic Concepts and Methods" which is an introduction into this field. Johann Gasteiger has had a distinguished career in Chemistry and is well known for his seminal contributions to Chemoinformatics. He was the recipient of the 1991 Gmelin-Beilstein Medal of the German Chemical Society for Achievements in Computer Chemistry; the 2005 Mike Lynch Award of the Chemical Structure Association; the 2006 ACS Award for Computers in Chemical and Pharmaceutical Research for his outstanding achievements in research and education in the field of Chemoinformatics and the 1997 Herman Skolnik Award of the Division of Chemical Information of the American Chemical Society. Thomas Engel is a specialist in Chemoinformatics who studied chemistry and education at the University of Würzburg and spent a significant tenure at the Computer-Chemie-Centrum at the University of Erlangen-Nürnberg, followed by the Chemical Computing Group AG in Cologne and is presently at the Ludwig-Maximilians-Universität, Munich.

As editors, they have brought together a wide range of experts and topics which will inform, educate and motivate the reader to delve deeper into the subject of Chemoinformatics. The new edition provides both the foundations for Chemoinformatics and also a range of developing topics of active research, providing the reader with an introduction to the subject as well as advanced topics and future directions. This new edition is complemented by the "Handbook of Chemoinformatics: From Data to Knowledge" (by the same editors). It...