Gideon the Cutpurse by Linda Buckley-Archer.
I was only halfway through this novel when I checked to see if the author had written any other books, it was that good. Kate and Peter were chasing their misbehaving Golden Retriever down the halls of Kate’s father’s scientific lab when an experiment goes awry and flings them back to England in 1763. Fortunately, Gideon, a cutpurse with a kind heart sees their dramatic arrival and decides to keep an eye on them. This is especially fortunate with Tar Man, a dangerous criminal, on the loose. The children meet highway men, thief takers, Erasmus Darwin, and King George in their quest to return to their own time. Historical details on clothes, and customs such as public hangings, as well as many asides on the smells of the period enhance this intriguing adventure story. This novel is intended for teen readers but many adults will enjoy it also.