thoughtful study and studious thought

[Tinkerbell]

An accomplished wizard once lived on the top floor of a tenement house and passed his time in thoughtful study and studious thought ??. What he didn't know about wizardry was hardly worth knowing, for he possessed all the books and recipes of all the wizards who had lived before him; and, moreover, he had invented several wizardments himself.

thoughtful study and studious thought ??.

What he didn't know about wizardry was hardly worth knowing = he knew about wizardry almost everything?

 

[Tinkerbell]

Thank you, Gillnetter :-D