All 3 Uses of

muster
in
Love Medicine

I thought the police would leap across the table and collar Gerry, then tie me up, and I had just mustered up the courage to get arrested with a decent struggle when I noticed that the state police were still standing in the door.†
p. 326.1 *

mustered = gathered

It came in handy, as well, when he made a sale, although civilian life had long ago taken the edge off his intensity, as it had his muscles, his hero's stubborn, sagging flesh that he could still muster in a crisis.†
p. 113.1

I had to get there prompt on night number six, leave just before dawn broke, give and take all the pleasure I could muster myself to stand in between.†
p. 131.2

Definitions:

(1) (muster as in: muster strength or the crew)
to gather
The exact meaning of this sense of muster is often subject to its context. For example:
- "mustered her courage/strength/a smile" -- to gather from within
- "muster the soldiers/crew" -- to gather -- typically for inspection
- "muster volunteers/votes" -- to gather enough to do something
(2) (muster as in: didn't pass muster)
inspection -- especially of soldiers or a crew
(3) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

More rarely, muster can refer to a counting or census. Much more rarely, muster can refer to a call to duty such as compulsory military service or jury duty. In that sense, you may see the expression muster in or muster out. Still more rarely, a muster can refer to a group of peacocks.