Islam's Lunisolar Calendar and the Celestial Year-Clock

Combining facts of natural science with interpretation of the Holy Qur'an and prophetic hadith, from a perspective of unwavering faith in God the Creator and Sustainer of All, Muslim author Mark Brustman presents a bold but broadly evidenced thesis: the strictly lunar calendar followed by Muslims of every sect around the world is not the calendar that was intended for Islam and revealed to and taught by the Prophet Muhammad. The Prophet's calendar was lunisolar, with Ramadan tied to the southward equinox. Instead, the Muslim world can credit the second caliph 'Umar ibn al-Khattab for launching the rotation of its seasonally unanchored calendar months. This was likely done to maintain order in 'Umar's fast expanding empire, by shielding Jewish leaders from Qur'anic criticism of their calendar manipulation as detailed in the Babylonian Talmud.
Each chapter approaches the argument from a different angle, ranging from the Qur'an's mandate of a lunisolar calendar, to hadith reports suggesting Laylat al-Qadr as the solar anchor of the lunar months, to the heretofore elusive reconciliation of the dates and seasons of events in the Prophet's life, to refutation of the false claim that Qur'an verses 9:36-37 justify the strictly lunar calendar, to the contortions some scholars have gone through to support this false claim, to the more or less veiled ways in which several classical Muslim scholars, including Tabari, undermined the strictly lunar calendar. Primary sources of the Islamic classical era are quoted in the original Arabic with English translation, so readers can examine the texts for themselves and recover the true calendar of Islam.
If all that were not enough, Brustman has identified a mysterious pattern in the solar and lunar cycles, unknown to the tabular Babylonian and Jewish lunisolar calendars, that goes beyond the 19-year Metonic cycle to establish a further lunisolar cycle repeating every 6479 years.