Contrary to what the cynics may say, many non-scientists are captivated by the same Big Questions that keep physicists and astronomers so busy. This book is an attempt to share my fascination with them. I am grateful to the people at Amsterdam University Press for encouraging me to do so. Even though this book is primarily meant for the general public, I wish to hold it to the professional standards of a scholarly work. I am most grateful to six scientists for the time and effort they spent in assessing an earlier version of my book. It is customary that such referees remain anonymous, so that they are entirely free to tell the author their opinions. Therefore, I cannot thank them in person for their criticism and insight, but my gratitude remains undiminished nonetheless.

Fortunately, the seventh referee, Charlotte Lemmens, did not remain anonymous at all, which gives me the joyful opportunity to thank her once more for her detailed and intelligent assessment. I hope that she may consider this result as yet another bright feather in her guardian angel wings.