Old English Patent Medicines in America By: George B. Griffenhagen

Old Rambling House By: Frank Herbert

Omega, the Man By: Lowell Howard Morrow

On Books and the Housing of Them By: William E. Gladstone

On Handling the Data By: M. I. Mayfield

On Some Fossil Remains of Man By: Thomas Henry Huxley

On the Advisableness of Improving Natural Knowledge By: Thomas Henry Huxley

On the Antiquity of the Chemical Art By: James Mactear

On the Genesis of Species By: St. George Jackson Mivart

On the Method of Zadig By: Thomas Henry Huxley

On the Origin of Species: or, the Causes of the Phenomena of Organic Nature By: Thomas Henry Huxley

On the Parts of Animals By: Aristotle

On the Reception of the 'Origin of Species' By: Thomas Henry Huxley

On the Relations of Man to the Lower Animals By: Thomas Henry Huxley

On the Significance of Science and Art By: Leo Tolstoy

On the Study of Zoology By: Thomas Henry Huxley

On the uncertainty of the signs of murder in the case of bastard children By: William Hunter

On the Various Forces of Nature By: Michael Faraday

On War By: Carl von Clausewitz

One Hundred Proofs That the Earth Is Not a Globe By: William Carpenter

One Martian Afternoon By: Tom Leahy

One Out of Ten By: J. Anthony Ferlaine

One-Shot By: James Blish

Oneness By: James H. Schmitz

Ontario Teachers' Manuals: Nature Study By: Ontario. Ministry of Education

Operation Earthworm By: Joe Archibald

Operation Haystack By: Frank Herbert

Operation Lorelie By: William P. Salton

Operation R.S.V.P. By: H. Beam Piper

Optical Projection Part 1: Projection of Lantern Slides By: Russell S. Wright

Oracles of Nostradamus By: Charles A. Ward

Organic Evolution By: Richard Swann Lull