Volume 5, Issue 4 of Acta Astrophysica Taurica contains materials presented at two All-Russian astronomical conferences with international participation: 'Magnetism and Activity of the Sun and Stars - 2021', from August 31 to September 3, 2021, in Nauchny and 'Magnetism and Activity of the Sun - 2022', held at CrAO RAS, Nauchny, from August 22 to 26, 2022. The collection is intended for specialists in astronomy and astrophysics.