I'm currently taking a U.S. History class at my college and we are using the textbook, "Give Me Liberty!" Seagull forth edition by Eric Foner. Like any text book, it summarizes and makes claims about events that have taken place in the past, but it also does not make citations for them at all. Granted, in the preface the author notes how there have been "Innumerable historians on whose work [he has] drawn in preparing for this volume" and that "In the suggested reading list at the end of each chapter offers only a brief introduction to the vast body of historical scholarship that has influenced and informed this book." He then lists 45 professionals from around the nation that he has received comments, criticisms, and suggestions from. With that credit being given however, the question still remains: can we be certain in the claims made throughout this textbook, even though there are no citations for any of the claims? I ask this question because I have been taught the importance and necessity of citing your work when pulling information from other sources. Is there a point, however, where this rule no longer applies? Or am I missing something all together?
Thanks!
Edit: Wording
Most textbooks don't give footnotes, actually. There's a widespread belief among publishers that footnotes make a book look difficult to read, and scare away students. As a result, many popular press books - and almost every textbook - don't provide notes for its arguments. (Though there's often a For Further Reading... section at the end.) This lack of citations is further justified by the perception (whether accurate or not) that overview textbooks are giving you the story upon which everyone agrees; hence their contents are essentially 'common knowledge'.
This isn't an approach you want to follow in your own writing, and I'm personally not entirely comfortable with it in textbooks myself. But, for better or worse, it's how publishers encourage textbook writers to write.
So you're correct to question to this, but ultimately it's not a direct reflection of the author's credibility. It's, instead, a statement about how textbook publishers underestimated your intelligence by assuming that you wouldn't want to see sources cited.