Garth Fletcher is a Professor of Psychology at Victoria University of Wellington. He is a fellow of five societies including the Royal Society of New Zealand, the Association for Psychological Science, and the Society for Personality and Social Psychology. He has recently served as an associate editor for three different social psychology journals, including the Journal of Personality and Social Psychology. He has published over 120 articles and book chapters and has authored and edited 6 books, including the current book: The Science of Intimate Relationships.

Jeffry A. Simpson is a Distinguished University Teaching Professor in the Department of Psychology at the University of Minnesota, where he is the director of the Doctoral Minor in Interpersonal Relationships Research. He has served as the editor of Personal Relationships and the Journal of Personality and Social Psychology: Interpersonal Relations and Group Processes. Simpson has also been the president of the International Association for Relationship Research and has published nearly 300 articles and chapters along with more than a dozen edited books.

Lorne Campbell is a Professor of Psychology at the University of Western Ontario. Lorne is a recognized expert in the field of interpersonal relationships and is a proponent of open science (see https://osf.io/sa9im/). He is a fellow of the Society of Experimental Social Psychology and the Society for Personality and Social Psychology. He has served as the editor of Personal Relationships and as an associate editor of Personality and Social Psychology Bulletin and Social Psychological and Personality Science.

Nickola C. Overall is a Professor of Psychology at the University of Auckland, New Zealand. Nickola has published over 100 articles and book chapters and is a fellow of the Association for Psychological Science and the Society for Personality and Social Psychology. Nickola has been an associate editor of Personal Relationships and Social Psychological and Personality Science and is currently an associate editor of the Journal of Personality and Social Psychology: Interpersonal Relations and Group Processes.

Welcome to the second edition of The Science of Intimate Relationships, first published in 2013. We (the authors of this book) have all been using it in our classes for several years, along with many of our colleagues. We have been receiving good feedback from our own students about the book, along with a number of academics who have been using the book in countries all over the globe. They have also given us various suggestions about making it even better. The relationship field is even more popular and interdisciplinary than it was in 2013, and the pace of new publications and research has been remorseless. Controversies have been resolved, new ones have appeared, some fields of study that were embryonic in 2012/2013 have blossomed, and the sciences relevant to Relationship Science have moved along. Time for a second edition.

The most important features about the book remain the same as the first edition. It is still aimed at university courses on relationships taught at an upper‐level undergraduate or postgraduate level, it retains its rigor and lively style, and it is still avowedly interdisciplinary. The much‐loved front cover by the noted artist and academic Calum Colvin, has also been retained. The story behind this picture on the cover deserves a re‐telling from the first edition. The image is a contemporary reading of a classic statue from the eighteenth century depicting Cupid and Psyche by Canova (currently in the Musée du Louvre). The Greek legend of Cupid and Psyche can be traced to the second century AD. It starts with Cupid being sent by Venus (Cupid's mother) to pierce Psyche with his arrow so she would fall in love with a vile creature (placed there by Venus) when she awoke. Venus was jealous of Psyche because of her renowned beauty. The plan goes awry when Cupid accidentally pricks himself with his own arrow and falls head over heels in love with Psyche. The legend, as legends do, goes through many twists and turns before they finally get together and live happily ever after (literally, as Psyche was rendered immortal like Cupid).

If you look closely at the picture on the cover, you can see that it is not quite what it seems at first glance. It was created in a rather complicated fashion by arranging a collage of material from an ordinary lounge (a radio, a couch, a light bulb, a book, and so forth), then partly painting and photographing the arrangement from a certain angle. The image is finally printed as a large‐scale photograph. This picture illustrates a major theme in this textbook; namely, that love, passion, and intimacy are powerful forces that can seem exotic, yet at the same time are woven through the fabric of ordinary life, forming part, as they do, of the bedrock of human nature.

So what has changed in the second edition. First we have added two new chapters dealing with the links between intimate relationships and health (Chapter 5) and family and friends (Chapter 8). Second, we have updated the references and revised various sections to represent important developments over the last six years. It is, therefore a little longer than the last edition, but we have vigilantly avoided any hint of unnecessary verbiage.

We continue to owe a tremendous debt to our colleagues who reviewed and read the chapters from the first edition, including Gina Grimshaw and Alan Dixson. We thank, again, the team at Wiley‐Blackwell for their support, patience, and enthusiasm for the project, and we owe a great debt of gratitude to the untiring and expert help of Laina Isler for creating new graphs, sorting out the flood of copyright issues involved, sorting out the references, and expertly proofing the entire book. We could not have produced this edition without her considerable help.

Finally, we can think of no more fitting acknowledgment than for the first edition. We give grateful thanks to our respective partners and families for their understanding and support, especially when working on the book during countless evenings and weekends.

We hope you enjoy this edition, and come away with the same feelings we had after reviewing the creative flood of rigorous and exciting scientific work going on in Relationship Science – a mix of awe and respect.