Inconsistent spelling, hyphenation, capitalisation, etc. and lay-out have been retained, except as mentioned below. The same applies to repetitions, factual errors, mistakes, unclarities and contradictions in the puzzles, riddles etc. and in the solutions provided.

Depending on the hard- and software and their settings used to read this text, not all elements may display as intended.

Page I-7, Monster Magic Square: row 2 column 2 should be 48, not 41; row 3 column 9 should be 92, not 72.

Page I-30, magic triangle, bottom row 0 should be 8 (as in the solution on page I-150).

Page I-89, "on opposite sides of the central line": this should be read "on opposite sides of the central lines" (both horizontal and vertical).

Page I-130, mens’ tears: as printed in the source document.

Page I-131, An Illusion of Type: the phenomenon described may not work with every font. Therefore the right-side-up and upside-down text lines have been inserted as an additional illustration.

Page I-136, For the Children, last sentence: the opposite is true: If this is an even quantity the coins or sweets in the right hand are odd, and in the left even; if it is odd the contrary is the case.

Page II-130, number 81: some words were misprinted or missing altogether; these have been added based on the context: ... the man [fe]ll sick ...; [Ho]w ought his estate ...; and ... to [the] widow, son and daughter.

Page II-148, Notable Chronogram: IAVDES should have read LAVDES, which would result in the year 1894 (when the organ was blessed).

Page II-176, Solution LXXX: The positions of the dots are indicated in the text only, not in the diagram.

Page II-204, Solution 65, 12 + ¹/₂ = ¹³/₂: the calculation only works if the 12 were replaced with ¹²/₂ (or 6), which would be in accordance with the description.

Page II-206, Solution 77: two and twenty pence should probably read two and twenty pence.

Page III-3 and III-111, No. III: The illustration in the question is not the same as the one in the answer.

Page III-25, Begins 2 U U U up: possibly an error for Begins 2 UU U up (cf. other repeated letters).

Page III-35, No. XXXV, five words: there are six words in the puzzle (and in the solution).

Page III-77, inspirÉd strain: as printed in the source document.

Changes made

Some obvious minor typographical and punctuation errors and misprints have been corrected silently.

Some minor lay-out inconsistencies have been standardised without further remarks; where necessary, table and text-elements have been re-arranged and aligned in accordance with the description given.

The part numbers have been inserted on the blank pages preceding each part.

Throughout the book, items from one category (preceded by an Arabic number) are occasionally printed split over two pages, with one or more items from other categories (often preceded by a Roman numeral) between the several parts. For this text, these split items have been recombined on the page where they originally started, and references to their respective parts have been deleted.

The part numbers (I, II and III) have been added to the page numbers for easier reference.

Items in dotted boxes do not occur as such in the original book but have been transcribed schematically from the illustration.

The illustrations on Page II-63 (No. LXIII) and II-65 (No. LXV) have been flipped horizontally, the illustrations on page II-68 (No. LXVIII) and II-78 (No. LXXVIII) have been rotated, all in order to correctly display the letters and numbers.

Page I-141: "cigars" changed to "cigares" (French, 2x).

Page II-99, 6¹ changed to 6¹/₂.

Pages II-113 and II-185, illustration: reference letter "F" added.

Page II-199: "there they sold" changed to "these they sold".

Page II-225, Solution 6: "f on d l over" changed to "a f on d l over".

Page III-7, No. VII: "BVT In trVth" changed to "bVt In trVth".

Page III-41, No. 67: "And if — —— is ’vert" changed to "And if an —— — ’vert".

Page III-46: "chÊrit" changed to "chÉrit".

Page III-54, No. LIV: in the printed document, the doors are marked (left to right) B - A - C, and the gates B - A - C as well. The gates’ marks have been changed to C - A - B in order to agree with the solution provided on page III-127.

Page III-67, illustration: unprinted asterisk added to the right-hand arm of the cross.

Page III-78: "a jamais" replaced with "À jamais".

Page III-108: "stats" replaced with "stets".

Page III-123, Solution XLIII: V inserted in bottom line cf. puzzle.

Page III-124: "stripes" changed to "strips" cf. puzzle.

Page III-128: "86 diamonds and 6 children" changed to "36 diamonds and 6 children".

Page III-132: Solutions LXVIII and LXXIV have been added to show the upside-down illustrations. Solution LXXVIII has been added to show the reversed illustration.