Who worked with you is important in academia. Mathematicians have the conceit of the Erdös number, which is closeness of association by collaboration, akin to six degrees of Kevin Bacon.

More generally, academic genealogy traces intellectual descent in terms of lines of supervision. Who were the geniuses who supervised the big brains who supervised the really competent people who had to put up with you?

So, my own traced history:

Lloyd Wood, Internetworking with satellite constellations, University of Surrey, 2001, supervised by George Pavlou.

I later put a router in orbit and did the first in-space tests for the Interplanetary Internet.

George Pavlou, Telecommunications Management Network: A Novel Approach Towards its Architecture and Realisation Through Object-Oriented Software Platforms, University College London, 1997, supervised by Peter Kirstein with Graham Knight.

Kirstein also supervised my examiner: Jon Crowcroft, Lightweight protocols for distributed systems, University College London, 1993.

Peter Kirstein, A solution to the equations of space-charge flow by the method of the separation of variables, Stanford University, 1957, supervised by Gordon S. Kino.

Kirstein was Kino's first doctoral student. They coauthored a paper and a later book on the same topic.

Gordon S. Kino, Perturbation Theory of Transmission Systems, Stanford University, 1955, supervised by Marvin Chodorow.

Kino was a prolific inventor. His papers.

Marvin Chodorow, Examination of a General Method of Calculating Energy Bands of Crystals with Particular Application to Metallic Copper, Massachusetts Institute of Technology, 1939, supervised by John Clarke Slater.

Chodorow improved microwave tubes.

John Clarke Slater, The Compressibility of the Alkali-Halides, University of Florida, 1923, supervised by Percy Williams Bridgman.

Slater was a prolific author.

Percy Williams Bridgman, Mercury Resistance as a Pressure Gauge, Harvard University, 1908, supervised by Wallace Clement Sabine.

Bridgman was awarded the 1946 Nobel Prize in Physics for his work on high pressures.

Wallace Clement Sabine, M. A. 1888, awarded by Harvard University. Supervised by John Trowbridge.

Sabine did not bother with a doctorate. He pioneered architectural acoustics.

John Trowbridge, S.B. 1865, awarded by Harvard University, 1873, supervised by Joseph Lovering.

Trowbridge was awarded his doctorate on the strength of his papers: A New Form of Galvanometer; On the Electromotive Action of Liquids Separated by Membranes; On the Electrical Condition of Gas Flames; Ohm's Law Considered from a Geometrical Point of View; Induced Currents and Derived Circuits.

Joseph Lovering, graduated from Harvard University, 1833.

Hollis Professor at Harvard for over fifty years - the chair that Bowditch had earlier refused.

Benjamin Peirce, graduated from Harvard University, 1829.

Peirce was an unapologetic slaver.

Nathaniel Bowditch, awarded an honorary Master of Art, 1802, Doctor of Laws, 1816, by Harvard University.

Bowditch was a navigator and mathematician who benefitted from piracy. He was offered and refused professorship chairs in mathematics, including Harvard's Hollis chair.

Academic Tree can show this graphically. For a view from Harvard of the value of a PhD, see William James' The PhD Octopus, The Harvard Monthly, 1903.

Other attempts at tracking academic ancestry:

• Randy Katz, University of Berkeley, California.
• Thomas Schaefer, North Carolina State University.

It's depressing that I know my PhD's heritage better than I know my own family tree.

Lloyd Wood.