Thor, will you please take care of . . . 

 Oh, it’s marvelous, absolutely marvelous. You just step inside and I throw a lever. And things spin and lights go on and off, and you wind up somewhere in the future. 

 On the way there, with not one sound, the dog passed away. Died on the front seat—as if he knew . . . and knowing, picked the better way. 

 This is all wrong! If I dare change their stone age way of life, it may affect the whole future of their race. 

 Out of the world’s three billion people there can’t be more than, say, a hundred women like Jessica Maxwell. 

 Dropping the letter, she held her head in her hands, closing her eyes as in the curved bone of her skull she heard all her possible courses of action jar together, future lifelines that annihilated each other. 

 Mike was a recent but ardent science-fiction fan. “I want to change it, Dr. Stuart,” he said earnestly. “I want to go back to four weeks ago and take away Tony’s Flexy.” He meant it, of course. 

 A series of parallel black lines, several inches apart, extended from it, some distance across the corridor floor. At the head of each was a brief inscription, in no alphabet he could recognize. But every ten feet or so a number was added. He saw 4950, 4951, 4952 . . . 

1. Time Out for Martin (20 Jun 1965) to 1215 England
2. Go West, Young Martian (12 Sep 1965) to 1849 St. Louis
3. The Time Machine Is Waking Up . . . (21 Nov 1965)    Jesse James from 1870
4. The O’Hara Caper (19 Dec 1965) back to lunchtime
5. Heir Today, Gone Tomorrow (2 Jan 1966) to 1920/45 Cleveland
6. When You Get Back Home . . . (27 Feb 1966) back to the morning
7. Martin Meets His Match (27 Mar 1966) Da Vinci from 1400s
8. Pay the Man the $24 (1 May 1966) to 1626 Manhattan

 What a planet for me to get marooned on. 

1. My Hero? (25 Sep 1965) to ancient Babylon
2. My Master, the Pirate (13 Mar 1967) to Captain Kidd’s time
3. My Master, Napoleon’s Buddy (3 Apr 1967)    to Napoleaon's time

 We’re at the marketplace, master. Oh, and there is Ali, the man who hit me. 

—from “My Hero?”

 We were lucky, that was all. We could have sent that camera back another thousand times, perhaps, and never caught a mastodon—probably never caught a thing. Although we would have known it had moved in time, for the landscape had been different, although not a great deal different. But from the landscape we could not have told if it had gone back a hundred or a thousand years. When we saw the mastadon, however, we knew we’d sent the camera back 10,000 years at least.
I won’t bore you with how we worked out a lot of problems on our second model, or how Dennis managed to work out a time-meter that we could calibrate to send the machine a specific distance into time. Because all this is not important. What is important is what I found when I went into time.
I’ve already told you I’d read your book about Cretaceous dinosaurs and I liked the entire book, but that final chapter about the extinction of the dinosaurs is the one that really got me. Many a time I’d lie awake at night thinking about all the theories you wrote about and trying to figure out in my own mind how it really was.
So when it was time to get into that machine and go, I knew where I would be headed. 

 As the first period of math class began, Mr. Komatsu—the fat math teacher—wrote down an equation on the board, and Kazuko began to frown. It was the very same problem they’d solved just the day before. But more than that, Mr. Komatsu had written the problem on the board at exactly the same time before, and Kazuko had been called to the front of the class, where she’d struggled for some time over the solution.