While Mrs. Mifflin was away, however, Roger’s routine was somewhat different.  After closing the shop he would return to his desk and with a furtive, shamefaced air take out from a bottom drawer an untidy folder of notes and manuscript.  This was the skeleton in his closet, his secret sin.  It was the scaffolding of his book, which he had been compiling for at least ten years, and to which he had tentatively assigned such different titles as “Notes on Literature,” “The Muse on Crutches,” “Books and I,” and “What a Young Bookseller Ought to Know.”  It had begun long ago, in the days of his odyssey as a rural book huckster, under the title of “Literature Among the Farmers,” but it had branched out until it began to appear that (in bulk at least) Ridpath would have to look to his linoleum laurels.  The manuscript in its present state had neither beginning nor end, but it was growing strenuously in the middle, and hundreds of pages were covered with Roger’s minute script.  The chapter on “Ars Bibliopolae,” or the art of bookselling, would be, he hoped, a classic among generations of book vendors still unborn.  Seated at his disorderly desk, caressed by a counterpane of drifting tobacco haze, he would pore over the manuscript, crossing out, interpolating, re-arguing, and then referring to volumes on his shelves.  Bock would snore under the chair, and soon Roger’s brain would begin to waver.  In the end he would fall asleep over his papers, wake with a cramp about two o’clock, and creak irritably to a lonely bed.

All this we mention only to explain how it was that Roger was dozing at his desk about midnight, the evening after the call paid by Aubrey Gilbert.  He was awakened by a draught of chill air passing like a mountain brook over his bald pate.  Stiffly he sat up and looked about.  The shop was in darkness save for the bright electric over his head.  Bock, of more regular habit than his master, had gone back to his couch in the kitchen, made of a packing case that had once coffined a set of the Encyclopaedia Britannica.

“That’s funny,” said Roger to himself.  “Surely I locked the door?” He walked to the front of the shop, switching on the cluster of lights that hung from the ceiling.  The door was ajar, but everything else seemed as usual.  Bock, hearing his footsteps, came trotting out from the kitchen, his claws rattling on the bare wooden floor.  He looked up with the patient inquiry of a dog accustomed to the eccentricities of his patron.

“I guess I’m getting absent-minded,” said Roger.  “I must have left the door open.”  He closed and locked it.  Then he noticed that the terrier was sniffing in the History alcove, which was at the front of the shop on the left-hand side.

“What is it, old man?” said Roger.  “Want something to read in bed?” He turned on the light in that alcove.  Everything appeared normal.  Then he noticed a book that projected an inch or so beyond the even line of bindings.  It was a fad of Roger’s to keep all his books in a flat row on the shelves, and almost every evening at closing time he used to run his palm along the backs of the volumes to level any irregularities left by careless browsers.  He put out a hand to push the book into place.  Then he stopped.