Reading the foundational primary researchers (Frankl, Cole, Wrzesniewski, Csíkszentmihályi, Deci & Ryan, Hill, Vallerand, Damon) gives you the empirical scaffolding. Reading the major synthesis books (Wong’s second-wave positive psychology, Mogi’s ikigai, Brooks’s Second Mountain, the Putnam & Campbell synthesis on religion) gives you the integrative picture. Reading the philosophical and humanistic traditions (Aristotle, Frankl, Arendt, Berry, MacIntyre, Charles Taylor, Bellah) gives you the intellectual context within which the empirical findings make sense. The combination is more useful than any single track.