If you would like a clear and concise summary of virtually any issue in Halacha, no matter how complex, then I highly recommend R' Moshe Sternbuch's Teshuvos V' Hanahagos. He generally cites and discusses only the important sources on an issue with little or no sidetracking (see his introduction).
In many of his earlier Teshuvos (dating from his tenure as a Rov in S. Africa), he demonstrates the sensitivity that Prof. Daniel Sperber
seems to value so much in a posek. My favourite Teshuva concerns a Baal Teshuva who was raised for many years by a step-mother before becoming frum. The dificulty is that he is not even able to shake hands, let alone kiss or hug her, something that would obviously casue no few problems. R' Sternbuch suggests that he give half a hand which is not
derekh chibah and therefor permitted. Lest this seem like no big deal, note that as opposed to the German posekim[1], R' Sternbuch considers handshaking to be not only a Torah violation but an actual אביזרייהו דעריות and he is now Raavid of the Edah HaChareidis not well-known for leniency in these matters.
In D. Horowitz's
article on "R. Moshe Sternbuch's Halakhic Novellae", he discusses the innovative nature of R' Moshe's novellae which, as opposed to the novellae of the yeshivos, have direct halachic ramifications.
Prof. Sual Lieberman used to say:
כשאדם אומר חידוש הרי לבטח כבר קדמו אדם אחר, ואם לאו - הרי שאין החידוש אמיתי. אם בכל זאת חושב הוא שהחידוש נכון, אזי צריך הוא לשאול את עצמו מדוע לא אמרו את החידוש הזה לפניו
Perhaps, this might be true of some of R' Sternbuch's chiddushim. As I was studying Yevamos[2], the following occurred to me. [Although after reviewing the
sources, I see that this is not a very good example as R' Sternbuch is following the strict ruling of the MB who resolves the apparent contradiction, but I decided to write this anyway - בשביל דבר שנתחדש בו.]
[In one of his Teshuvos (4:118 and other places), he suggests that if on Shabbos one needs to have a child turn on a light, it is best to have someone else's child, in order to avoid the extra prohibition of שביתת בנו. This prohibition, although mentioned in Mechilta, is nowhere mentioned in the Mishna or Talmud. In fact, in Yevamos 114a we read:
ש <עובד כוכבים> {נכרי} שבא לכבות אין אומרים לו כבה ואל תכבה מפני שאין שביתתו עליהם קטן הבא לכבות אומרים לו אל תכבה ששביתתו עליהם א"ר יוחנן בעושה על דעת אביו
as Rashi explains , the problem is that it is as if the father directly commands the kid to extinguish but w/o this difficulty, it would be permitted and the father does not have to stop his son because of שביתת בנו. The exact status of the Halachic Midrashim, when in conflict with the Talmud still needs to be clarified.]
R' Sternbuch is a descendant of the Gra [3], so when I had an opportunity to meet him I asked him what he considers to be the purpose of the hagahot hagra on Shas (Bavli). The hagahot seem to differ very much in style between tractates. At the time I was learning Bava Metzia in which most of the hagahot simply mention that "the Rambam disagrees and the Rosh is in doubt" and the like, which don't seem to add anything substantial to the sugya. R' Sternbuch suggested that the Gr"a means to pasken like that Shita in these cases but I must confess that this doesn't seem to me to be sufficent explanation. Can anyone check if Y. S. Spiegel discusses this type of hag'ah in his Amudim?
[1] See
here, I have unearthed some more sources on this Minhag Ashkenaz (not one you will find mentioned in
Shorshei) which I hope eventually to place here.
[2] It is interesting that the difficulty of Yevamos was so well-known that it is even referred to in Karaite polemics - see Shraga Abramson's article in Sinai 52.
[3] As he signs his name, נין ונכד להגר"א, I saw R' Chaim Kanievsky refer to a "certain Gadol who signs this way and I told him they are both false" - as in Bereishis 21:23 that the terms refers to the 2nd and 3rd generation but not beyond (see
here).