What is your opinion of the book "Fiqh as-Sunnah" by Sayyid Sabiq, and do you recommend it to me as a doctor who does not have time to study large books, or what abbreviated Fiqh books do you recommend to me?

The book Fiqh Al-Sunnah by Sayyid Sabiq is a good contemporary fiqh book, characterized by its medium size, easy style, lack of sectarian bias, and reliance on evidence from the Qur'an, Sunnah, and scholarly consensus. It makes understanding easy for the general Muslim public.

However, the book has hadithic, methodological, jurisprudential, and usuli (foundational principles) observations, including: the presence of weak or flimsy hadiths, or attributing them to books other than the Sahihayn (Bukhari and Muslim) when they are in fact in them, or attributing them to books other than the Sahihayn when they are not in them. Sometimes, it presents issues without evidence, or prefers an opinion that does not deserve preference.

These observations do not mean that the book should not be used; rather, one should be aware of them. It is recommended to acquire an authenticated version of it and to consult Shaykh Al-Albani's book Tamam Al-Minna fi Al-Ta'liq 'ala Fiqh Al-Sunnah, bearing in mind that some of the observations are matters of ijtihad (independent reasoning). It is also recommended to read Al-Fiqh Al-Muyassar as a starting point and to consult reliable fatwa books.