Books like The Druids by Stuart Piggott

"A world expert on how trees chemically affect our environment, Diana Beresford-Kroeger has woven together ecology, ethnobotany, horticulture, spirituality, science and alternative medicine in The Global Forest to capture their enormous significance to us - and our future. Trees absorb pollutants from the ground, comb particulates from the air and house beneficial insects. But what they do chemically in the environment is something we're only beginning to understand. Trees not only breathe and communicate; they also reproduce, provide shelter, medicine and food, and each of these forty interlocking essays picks out a different aspect of the life of the forest, explains it and then shows why it is so vitally important. Combining the precision of a scientist with the lyricism of a poet, Diana Beresford-Kroeger has written an unforgettable work of natural history that shows how we really can save the Earth, one tree at a time."--Publisher description.

Jack, an apprentice bard, and his Viking companion Thorgil face a vengeful mermaid spirit in the Norse‑mythic waters around the Orkney Islands, launching a perilous quest among the fin‑folk of Notland.

Ainvar, a fifteen‑year‑old apprentice to the chief druid of the Carnutes, joins forces with Prince Vercingetorix to unite Celtic tribes and resist Julius Caesar’s Roman legions.

A teenage sibling duo visit cousins in Ireland, and when a suspicious farmhand’s powers awaken, they are hurled back in time to the legendary clash between Cú Chulainn of Ulster and Queen Maeve of Connaught.