The Shield of Time

Poul Anderson's a great writer and this ages better than most sci-fi that traces back to pulps. It's hard though not to spend nearly every story wondering if the agents cause so much chaos then “why not just eliminate the Time Patrol itself?”

Beringia, the Wanda Tamberly story, is the pick of the bunch.

Poul Anderson started publishing Time Patrol stories in 1955, when he was about 28, and he carried on writing them occasionally until 1995. Most of them are collected in [b:Time Patrol 261499 Time Patrol (Time Patrol #1-4 + 6 omnibus) Poul Anderson https://i.gr-assets.com/images/S/compressed.photo.goodreads.com/books/1386923670l/261499.SY75.jpg 1784576], and you should definitely read that first.This book is not really a novel, but a collection of further Time Patrol stories written in his 60s, when he was past his best. If you liked the original stories and want more, this might suit, although I don't find this book very satisfying and tend to skip chunks of it when rereading.There are three main stories here, with some intermissions in between.“Women and Horses and Power and War” is primarily set in the city of Bactra in 209 BC, and is a readable enough Time Patrol story starring Manse Everard, quite similar to the earlier ones, though not one of the best of them.“Beringia” is primarily set before 13,000 BC, starring Wanda Tamberly, who has a serious disagreement with her boss. Again, it's readable enough, but I'm not keen on this one.“Amazement of the World” is a long, rambling story primarily set in the Middle Ages, in which history is altered as though by the intervention of a time traveller; but in this case it seems that no time traveller is responsible, which makes the problem particularly difficult to fix. I enjoy some parts of this story, but as a whole it's rather puzzling and unconvincing. Manse and Wanda are both involved.