Behavior of Art of Electronics highpass filter depending on resistance value
You should read that sentence in the context of what was explained in the introductory chapters about signal sources and voltage dividers.

As can be shown the signal source will see the amplifier input as a simple resistance (R) in the passband.  Once you set the bandwidth (i.e. the RC product) you are left with one degree of freedom, i.e. choosing the R value.

The R value is chosen as a trade-off between a very large (ideally infinite) resistance (good to avoid attenuation, but bad for noise pickup) and a very low (ideally zero) resistance (no noise pickup, but no signal transfer either!).

To be more explicit, in the passband the circuit is like this:







simulate this circuit &ndash; Schematic created using CircuitLab

$$
V_{in} = V_s \cdot \frac{R}{R_s + R}
$$

So, if R is much bigger than Rs, then Vin will be almost equal to Vs (no attenuation). But making R bigger will increase the input impedance of the amplifier, thus increasing the chance for noise pickup (noise sources can couple capacitively to the input terminal, and they appear as high impedance sources, so we want their (noise) signal to be attenuated, hence low R).