・Revised the references to [ArLgSch] so as conform to the published (i.e., LaTeX) version ・Added an Appendix that discusses the validity of individual propositions, lemmas, corollaries, theorems, and examples of  [LgSch], [ArLgSch], together with a paragraph that refers to this Appendix in the Introduction ・Corrected a misprint in the first paragraph following Theorem A ("fs schemes" ---> "fs log schemes") ・Slightly modified the wording of the final sentence of the third paragraph of \S 0 ・Slightly modified the wording of the second sentence of the statement of the "continuity property" in \S 0 ・Modified the notation in Example 0.1 and the preceding discussion ("a" ---> "\alpha", "b" ---> "\beta") so as to  avoid confusion ・Corrected a misprint in the discussion immediately preceding the second display of Example 0.1 ("\infty P" --->  "\infty P^{pf}") ・Corrected misprints ("depend on \phi" ---> "depend on \psi", 2 instances) in Examples 0.1, 0.2 ・Slightly modified the discussion of log smooth morphisms in \S 0 ・Slightly modified the two sentences immediately preceding Example 0.3 ・Added a supplementary explanatory phrase to the discussion immediately following the third display of Example 0.3 ・Deleted Example 0.4 ・Slightly modified ("arbitrary log schemes" ---> "arbitrary fs log schemes") the final sentence of the fourth paragraph of \S 1 ・Corrected a misprint at the beginning of Definition 1.1, (ii) ("\rightarrowtail" ---> "\rightarrow") ・Added a supplementary explanation to the end of Definition 1.1, (iii) ・Corrected misprint in Definition 1.1, (iii); 2.9, (iii) ("though" ---> "through") ・Corrected a misprint in Definition 1.1, (iv) ("exact" ---> "strict") ・Modified the wording of the final portion of Proposition 1.3, (ii) ・Corrected an error in the statement and proof of Lemma 1.5, (i), and made corresponding modifications to the statement  and proof of Proposition 1.6, (i); the proof of Proposition 1.7; the portion of the second, third, and fourth paragraphs  of the proof of Proposition 3.2, (v), that concerns charts ・Slightly modified the phrasing of the statement and proof of Lemma 1.5, (ii) ・Simplified the exposition of the final portion of the first paragraph of the proof of Lemma 1.5, (iii), by eliminating  "J" and eliminated "J" from the second paragraph of this proof (1 instance) ・Slightly modified the phrasing of the first sentence of the second paragraph of the proof of Lemma 1.5, (iii) ・Slightly modified the phrasing of the statement of Lemma 1.5, (iv), surrounding the term "saturation" ・Slightly modified the phrasing of the initial portion of the statement and proof of Lemma 1.5, (vi) ・Corrected a misprint at the beginning of Lemma 1.5, (ix) ("\phi" ---> "\phi_0") ・Corrected misprints in the proofs of Proposition 1.6, Theorem 3.8 ("The completes" ---> "This completes") ・Corrected a misprint in the first sentence of the proof of Proposition 2.2 ("observe recall" ---> "observe") ・Slightly modified the phrasing of the portion of the proof of Proposition 2.2, (ii), concerning Proposition 1.4 ・Corrected a minor error ("projective line" ---> "N-dimensional affine space") in the first sentence of the proof of  Proposition 2.4 ・Deleted an unnecessary "i.e.," from the explanation immediately following the first display of the statement of  Theorem 2.6, (ii); Corollary 2.12, (ii); Theorem 3.6, (ii); Theorem 4.4, (ii); Theorem 4.5, (ii); Theorem 4.6, (iii) ・Corrected misprints in Theorems 2.6, (ii); 4.4, (ii); 4.5, (ii) ("if only if" ---> "if and only if", 4 instances in all) ・In the proof of Theorem 2.6, slightly modified the proof of the preservation of (i-i) ・Corrected a misprint ("be an arrow" ---> "an arrow") in the second sentence of the statement of Proposition 2.10 ・In the proof of Proposition 2.10, added an explanatory phrase to the fourth sentence of the proof of assertion (iii)  and slightly modified the discussion of positivity at the end of the proof of assertion (iii) ・Corrected a misprint at the beginning of Definition 3.1, (i) ("a object" ---> "an object") ・In the first sentence of the proof of Proposition 3.2, added a reference to Proposition 1.4, (iv) ・Added a supplementary explanatory phrase to the discussion of the unique display in the proof of Proposition 3.2, (iv) ・Slightly modified the phrasing in the first paragraph of the proof of Proposition 3.2, (v) ・Added an explanatory phrase to the discussion of "restrictions" at the beginning of the proof of Proposition 3.4, (ii) ・Corrected a misprint ( "(i-d)" ---> "(i-e)") in the portion of the proof of Theorem 3.6 concerning the preservation of  (i-d) ・Slightly modified the discussion of the relation to the approach of [LgSch] immediately following the proof of Theorem 3.6 ・Corrected a misprint in the discussion of the affine line immediately following the proof of Theorem 3.6 ・Deleted the discussion of unnecessary notation in the discussion immediately preceding Proposition 3.7 ・Reformulated Proposition 3.7 and made corresponding adjustments to the proof of Proposition 3.7, as well as to the  portion of the proof of Theorem 3.8 that concerns Proposition 3.7 ・Added Remark 3.7.1 ・Added a supplementary explanatory phrase to the discussion of "condition (a)" at the beginning of the proof of Theorem 3.8 ・Corrected misprint (unnecessary parentheses and an unnecessary superscript "log") in the fourth display of the  second paragraph of \S 4 ・Corrected a misprint in Definition 4.1, (ii) ("that such that" ---> "that") ・Added a reference for the term "purely archimedean" in the latter portion of the proof of Theorem 4.3 ・Slightly modified the explanation immediately preceding the first display of the proof of Theorem 4.5 ・Corrected a misprint ("analogues for SCH^log" ---> "analogues for SCH, SCH^log") in Theorem 4.6, (iii) ・Added some omitted conditions to the first sentence of the statement of Theorem 4.8, (i) ・Slightly modified the explanation surrounding [ArLgSch], Lemma 4.1, in the first paragraph of the proof of Theorem 4.8 ・Slightly modified the wording in the final paragraph of the proof of Theorem 4.8 ("a ... characterization" --->  "... characterizations") ・Corrected the bibliographical information for [Kato1], so as to conform (essentially) to the information given in MathSciNet