Figures 401 (upper), 402 (middle) and 403 (lower, A, B) from Chapter 16 (Cytoplasmic matrix and cytoskeleton) of 'The Cell, 2nd Ed.' by Don W. Fawcett M.D. Microtubules, assembled with (middle, lower panel B) and without microtubule associated proteins (MAPs, upper, and lower panel A) present. Spacing between the microtubules is more uniform when MAPs are present. Figures from Binder and Rosenbaum, J. Cell Biol. 79:500-515, 1978 (PMID:569158). A PDF copy of the accompanying chapter is available on the ASCB’s BioEDUCATE website.