One passage that caught my eye was about how David Björling, who frequently used recordings by Caruso in his teaching, also used Karl Martin Öhman as a role model.
"Öhman, who studied in Milano among other places, was considered a consummate bel canto singer. Martin Öhman mastered a wide range of opera repertoire and his career was most successful abroad. It's evident from historical sources that Öhman initially had problems establishing himself on our Swedish national stage. At the Royal Opera in Stockholm, it was considered that Öhman was 'not a real tenor', since his timbre was too dark."I found a sound clip here.
Interesting to find that the Swedish suspicion towards dramatic tenors goes so far back. Later (pg 320), Liljas describes Jussi's conflict (in terms of vocal technique) with John Forsell (artistic director of the Royal Opera) as representative of the struggle between the old influence of the French school and the national, or naturalistic, tradition. In this case, Jussi (and Öhman) rather represented the Italian school, or a cross between the Italian school and the naturalistic Nordic tradition.
Öhman later went on to teach Nicolai Gedda and Martti Talvela - marvellous singers both.
The thesis is quite interesting. Hopefully, I'll have time to read it thoroughly.