small-format paperback book; pocket paperback
revising (and supplementing); expansion
enlarged and revised edition
occasionally; now and then; from time to time
(good) result; outcome; fruits (of one's labors); product; accomplishment
decreasing birthrate and aging population; aging population combined with the diminishing number of children; declining birthrate and a growing proportion of elderly people; dwindling birthrate and an aging population; low birthrate and longevity
depopulation; declining population
serious; severe; grave; acute
subject; theme; homework; assignment; task; challenge
duration; continuance; survival; persistence; retention
difficulty; hardship; trouble; infeasibility; inability (to carry out)
the future (usually distant); future tense; the world to come
something to rely on; aid; someone to rely on; relative; reminder; memento
old work; old book; previously published book
anthology; selection of books
rash; eruption (in response to a skin irritant); influence; crazy about; having an affectation concerning all things surrounding something (esp. a language, a culture, etc.)
advertisement; advertising; announcement; notice
research society; study class (e.g. religious); seminar (e.g. presentation of research)
study; library; bookstore; bookshop; publishing company
research division; research club (e.g. at school, university)
arts and sciences; liberal arts
Ikeda Kikan (scholar, 1896-1956)
argument; discussion; theory (e.g. of evolution); doctrine; essay; treatise
re-examination; review; reconsideration; reappraisal
ordinary; common; free of charge; unaffected; as is; only
truth; reality; seriousness; logical truth; printed style writing; star performer
outline; survey; compendium
famous book; masterpiece (literary work)