E. G. Boring (1950, p. 379) concludes his section on G. E. (Georg Elias) Müller with the quote,

... As a power and an institution he [G.E. Müller] was second only to Wundt.

which, however, seems like an understatement when the range of laudatory quotes, which include

an attribution of the origin of Titchener's structuralism to Müller

G. E. Müller at one time placed the work Komplextheorie in opposition to Gestalttheorie, but the word complexes has a meaning pre-empted by psychoanalysis ... Titchener similarly onced used for this position [Komplextheorie] the term 'structural' psychology; ... Gestaltpsychologie was even once translated into English "structural psychology," thus adopting the name of tis chief enemy. (p. 431)

and, conversely, that Müller

G. E. Müller was closest to Titchener's position. (p. 419)

describes Müller's role in psychophysics as

... becoming on Fechner's death [1887] the leader in psychophysics ... (p. 374),

characterizes Müller's contributions to memory as

Ebbinghaus had opened up a field [memory] which the patience of G. E. Müller and his associates was soon to develop ... (p. 388),

contrasts it with Wundt's research on memory

[Wundt's studies] made little impression as compared with the effective research upon memory by Ebbinghaus and G. E. Müller that belongs to the same period. (p. 343),

describes Müller's importance for color theory

Müller adopted Hering's theory of the three reversible photochemical substances ... and added his concept of cortical gray as the zero-point from which all color sensations diverge. (p. 376),

calls Müller's color theory

a theory so well known as often to be called Hering's theory, which it includes. (p. 376),

summarizes Müller's research interests

In these three fields [psychophysics, memory, color], he took over problems from their originators, criticized them, corrected them, extended them and centered research about them. (p. 374),

includes Krohn's (1893) portrayal of Müller's Göttingen laboratory

'in many respects the best for research work in all Germany.' (p. 374),

and says, of Müller's students

The men who worked under him at Göttingen furnish the second most distinguished group of names of German psychologists, for the students of Wundt must surely rank first. (p. 374).