When one of us (JFW) wrote an earlier introductory text in electron spectroscopy the aim was to fill a gap in the market of the time (1990) and produce an accessible text for undergraduates, first‐year postgraduates, and occasional industrial users of XPS and AES. In the intervening years the techniques have advanced in both the area of use and, particularly, in instrument design. In XPS, X‐ray monochromators are now becoming the norm and imaging has become commonplace. In AES, field emission sources are to be seen on high‐performance systems. Against that backdrop it was clear that a new, broader introductory book was required that explored the basic principles and applications of the techniques, along with the emerging innovation in instrument design.

We hope that this book has achieved that aim and will be of use to newcomers to the field, both as a supplement to undergraduate and master's level lectures, and as a stand‐alone volume for private study. The reader should obtain a good working knowledge of the two techniques (although not, of course, of the operation of the spectrometers themselves) in order to be able to hold a meaningful dialogue with the provider of an XPS or AES service at, for example, a corporate research laboratory or service organisation.

Further information on all the topics can be found in the Bibliography and the titles of papers and so on have been included along with the more usual citations to guide such reading. The internet provides a valuable resource for those seeking guidance on XPS and AES and rather than attempt to be inclusive in our listing of such sites we merely refer readers to the UKSAF site and its myriad of links. Finally, we have both been somewhat perturbed by the degree of confusion and sometimes contradictory definitions regarding some of the terms used in electron spectroscopy. In an attempt to clarify the situation, we have included a glossary of the more common terms. This has been taken from ISO 18115 and we thank ISO for permission to reproduce this from their original document.

It is now some 16 years since the publication of the first edition of this book. We have both been gratified by the positive manner in which it has been received by the community, testament to the need for an introductory text written by experienced practitioners. It gives us much satisfaction to see it in research and contract labs across the globe and frequently referenced in undergraduate and postgraduate reports. It thus appears to have fulfilled the perceived need outlined in the Preface to the first edition.

This perhaps begs the question ‘why wait sixteen years to produce the second edition?’ The answer to this is probably familiar to many practicing scientists and engineers in that the plan had informally been in place for several years, as had a formal contract; it was merely a question of allocating time in busy schedules.

The aim of the text remains the same, as enunciated in the first edition, and we have retained the same overall format. Basic principles remain, but instrumentation is constantly changing and improving as manufacturers seek better and better performance and functionality from their products. We have tried to reflect such developments in the text and make sure that it is as up to date as possible. In particular, we deal with a number of recent innovations in a manner accessible to newcomers to surface analysis. These include:

• Gas cluster ion sources.
• Newly developed high‐energy X‐ray sources (CrKα and GaKα) that are now available on commercial XPS systems.
• Near ambient pressure XPS, (a technique which is in its infancy but where the UK is arguably developing a lead).
• Fully automated, entry‐level, high‐performance systems.

Certain areas, such as sample preparation, sample mounting, quantification, peak fitting, energy loss background analysis, multi‐technique analysis and multi‐technique profiling are treated in more detail than before.

The year of publication (2019) is the Golden Jubilee of the launch of XPS and AES as commercially available analysis methods. It is a rather salutary thought that both of us have been involved with applied surface analysis for more than three quarters of this time, which gives us cause to reflect on the many innovations that have taken place during this time. As a celebration of 50 years of XPS we include images of one of the first commercial XPS systems and a sectioned analyser from such a system, overleaf.

As they say at all Golden Jubilee celebrations ‘Here's to the next fifty years!’

There are many who have contributed ideas and data to this book; current and former colleagues and students in particular. Specifically, those in The Surface Analysis Laboratory at the University of Surrey (Drs Marie‐Laure Abel, Simon Bacon, Jorge Bañuls Ciscar, Rossana Grilli, Chris Mallinson, Sabrina Tardio) and Drs Richard White, Tim Nunney and the staff at Thermo Fisher Scientific, have provided much new data to replace or complement that provided for the first edition. Dr Andreas Thissen at SPECS Surface Nano Analysis GmbH provided information and examples related to near ambient pressure XPS. In this, the golden jubilee year of XPS and AES, most of the innovators associated with XPS in the early days are no longer active. One notable exception being Professor Jim Castle who continues to edit a journal, publish papers, sit on ISO/TC201 and present work at conferences, in addition to being a source of inspiration to all associated with The Surface Analysis Laboratory at the University of Surrey.

Certain figures and data have been reproduced from other sources and we thank the copyright holder's for their permission to do so. In particular, the Wiley journal Surface and Interface Analysis has provided many valuable illustrations of the application of the techniques of XPS and AES. The cover design makes use of original graphics by Dr Robin Simpson (Thermo Fisher Scientific) and features the Nexsa™ automated XPS system.

The following figures are based on the data and other material provided by these organizations: