May one place an open Sefer upside down on its face, such as for a place holder?
It is forbidden to turn a Sefer over onto its front [open] part. If one found a Sefer in such a position, he is to turn it over. [Unfortunately, many people are not careful in this matter, and when they are called to the Sefer Torah [for an Aliyah], or need to take leave for other matters, the Sefer that they are reading, whether a Chumash or Tehillim and the like, they turn it over on its face [to save the page]. These people will unfortunately receive retribution [for belittling the honor of the Sefer]. Those who chastise people who do so, will be blessed.]
· It is forbidden to place an open Sefer upside down to rest on its pages, with its cover facing up.
· If one finds a Sefer in such a position he is to overturn it.
· If one sees someone who does so, one is to gently make him aware of the prohibition.
Is one to kiss the Sefer if he finds it upside down and turns it over?
May a Sefer on the shelf be placed upside down?
It is forbidden for a Sefer to be placed upside down, with its top part on the bottom.
May a closed Sefer rest upside down on a table, with its front cover on the table and back cover facing up?
[Although some question the source and logic for prohibiting this by our printed Sefarim today which have pages on both sides, practically, it is not to be done, as it is viewed by the populace as being disrespectful to the Sefer. Nonetheless, certainly the main prohibition which unfortunately less people follow or are aware of, is as stated above, to turn an open Sefer in its face.]
 Rama Y.D. 282:5; Darkei Moshe 282; Eiruvin 98a regarding Stam; Maharil Likkutim Pei; Sefer Chassidim 943; Chayeh Adam 31:45; Aruch Hashulchan 282:11; Ginzei Kodesh 2:24; See Avnei Yashpei 3:94
 Including Kisvei Kodesh, Halachos and Agados. [See Michaber ibid regarding throwing, and the Rama’s words are a continuation of his statement]
 Birkeiy Yosef 282 in Shiyurei Bracha in name of Radak [All the above words are a direct quote]
 Maharil Likkutim Pei
 See Ginzei Kodesh 2 footnote 39
 See Darkei Moshe 282; Sefer Chassidim 943; Maharil Likkutim Pei; Aruch Hashulchan 282:11
 See Bnei Banim 1:209 of Rav Henkin