Hi @EconomiCurtis, thanks for the suggestion. Replacing text_body with html_body does replace fixed-width font with normal-looking font, but when I send this with send_message, I still don't get the gmail signature coming through, and neither the gmail-specified from name nor the name I specify in from; instead the address itself appears in the from field. Any ideas? Thanks.
suppressPackageStartupMessages(library(gmailr))
mime() %>%
from("My Fancy Name") %>%
subject("Hi friend!") %>%
html_body("This is the substance of the message.")
#> $parts
#> $parts[[1]]
#> NULL
#>
#> $parts[[2]]
#> $parts
#> list()
#>
#> $header
#> $header$`MIME-Version`
#> [1] "1.0"
#>
#> $header$Date
#> [1] "Fri, 29 Jun 2018 18:49:34 GMT"
#>
#>
#> $body
#> [1] "This is the substance of the message."
#>
#> $attr
#> $attr$content_type
#> [1] "text/html"
#>
#> $attr$charset
#> [1] "utf-8"
#>
#> $attr$encoding
#> [1] "base64"
#>
#>
#> attr(,"class")
#> [1] "mime"
#>
#>
#> $header
#> $header$`MIME-Version`
#> [1] "1.0"
#>
#> $header$Date
#> [1] "Fri, 29 Jun 2018 18:49:34 GMT"
#>
#> $header$From
#> [1] "My Fancy Name"
#>
#> $header$Subject
#> [1] "Hi friend!"
#>
#>
#> $body
#> NULL
#>
#> $attr
#> NULL
#>
#> attr(,"class")
#> [1] "mime"
Created on 2018-06-29 by the reprex package (v0.2.0).