- E-bookErnst Haeckel's Art Forms in NatureErnst Haeckel
- E-bookThe History of Creation (Vol.1&2)Ernst Haeckel
- E-bookThe Riddle of the Universe at the close of the nineteenth centuryJoseph McCabe
- E-bookMonism as Connecting Religion and Science A Man of ScienceErnst Haeckel
- E-bookThe Riddle of the Universe at the Close of the Nineteenth Century [Second Edition]Ernst Haeckel
- E-bookThe Evolution of Man — Volume 1Joseph McCabe
- E-bookThe Wonders of LifeErnst Haeckel
- E-bookThe History of CreationErnst Haeckel
- E-bookLes énigmes de l'UniversErnst Haeckel
- E-bookArt Forms in NatureErnst Haeckel
- E-bookNatur & MenschErnst Haeckel
- E-bookNatur und Mensch (Illustriert)Ernst Haeckel
- E-bookLes énigmes de l'UniversErnst Haeckel
- E-bookThe History of Creation, Vol. I (of 2) Or the Development of the Earth and its Inhabitants by the Action of Natural CausesE. Ray (Edwin Ray) Lankester
- E-bookThe Last LinkErnst Haeckel
- E-bookLast Words on EvolutionErnst Haeckel
- E-bookThe History of Creation, Vol. II (of 2) Or the Development of the Earth and its Inhabitants by the Action of Natural CausesE. Ray (Edwin Ray) Lankester
- E-bookThe Last LinkErnst Haeckel
- E-bookFreedom in Science and Teaching. from the German of Ernst HaeckelErnst Haeckel
- E-bookEvolution in Modern ThoughtC. Lloyd (Conwy Lloyd) Morgan
- E-bookNatur und MenschErnst Haeckel
- E-bookFreedom in Science and Teaching. from the German of Ernst HaeckelThomas Henry Huxley
- E-bookThe History of CreationErnst Haeckel
- E-bookMonism as Connecting Religion and ScienceErnst Haeckel
- E-bookThe Evolution of Man — Volume 2Joseph McCabe
- E-bookDie WelträtselErnst Haeckel
- E-bookDie WelträtselErnst Haeckel
- E-bookDie WelträtselErnst Haeckel
- E-bookEvolution in Modern ThoughtC. Lloyd (Conwy Lloyd) Morgan
- E-bookThe Wonders of LifeErnst Haeckel
- E-bookFreedom in Science and Teaching. from the German of Ernst HaeckelErnst Haeckel
- E-bookThe History of CreationErnst Haeckel
- E-bookThe Riddle of the Universe at the close of the nineteenth centuryErnst Haeckel
- E-bookLes énigmes de l'UniversErnst Haeckel
- E-bookThe Riddle of the Universe at the close of the nineteenth centuryErnst Haeckel
- E-bookMonism as Connecting Religion and ScienceErnst Haeckel
- E-bookThe History of Creation, Vol. I (of 2) Or the Development of the Earth and its Inhabitants by the Action of Natural CausesE. Ray (Edwin Ray) Lankester